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The article deals with the history of the study of the northern shrimp, which lives in the northern part of the Sea of Okhotsk. Based on the materials collected in 2020, in comparison with 2018-2019, the course of fishing and catching of this object is analyzed. It is shown that the prospects of industrial development of this valuable object in the coming years do not cause concerns.

Pandalus species display the following features that make it difficult to apply traditional age-based stock assessment models: (i) difficulty of determining age in the absence of hard parts retained through the molt; (ii) sex change in which individuals mature first as males and then transform to females; and (iii) potentially strong influence of environmental conditions on recruitment population dynamics. In this context, we propose a seasonal, size-structured assessment model dedicated to stock assessment of hermaphroditic Pandalidae. The modeling framework incorporates a submodel for changes of length at sex transformation and functions to incorporate environmental effects on recruitment dynamics. The model can be directly fitted to length-structured data, overcoming the length to age conversion problem. The model has a seasonal time step that allows it to account for seasonal variations in biological processes and fishing patterns. The model provides stock assessment outputs, such as fishing mortality and stock biomass estimates, and sex-specific abundance-at-length. The model is applied to the exploited shrimp stock of Pandalus borealis in the Gulf of Maine as an example of its utility. The model proposed in this study is flexible and generic and can be applied to many other exploited stocks.

In the Estuary and Gulf of St. Lawrence, northern shrimp (Pandalus borealis) and Greenland halibut (Reinhardtius hippoglossoides) are usually found at depths > 150 m and thus frequently inhabit hypoxic areas (18–50% saturation). The impact of a one-week exposure to different levels of dissolved oxygen (100, 40, 30, and 20% saturation) at 5 °C was evaluated in adult shrimp and juvenile Greenland halibut; the effect of acute exposure to severe hypoxia was also assessed in Greenland halibut. The activities of key enzymes involved in aerobic (citrate synthase [CS], cytochrome c oxidase [COX]) and anaerobic (pyruvate kinase [PK], phosphoenolpyruvate carboxykinase [PEPCK], lactate dehydrogenase [LDH]) pathways, and of enzymes involved in antioxidant defence (superoxide dismutase, glutathione peroxidase [GPx], and catalase [CAT]) were measured. Quantitative real-time PCR analysis was also performed in Greenland halibut. In northern shrimp exposed to chronic hypoxia, muscle CS activity decreased by ~ 40%. Muscle LDH activity was significantly reduced, with a more intense reduction in males. At the same time, hepatopancreas GPx activity increased under hypoxia, and this response was stronger in males. Overall, the results suggest the presence of a threshold above 40% saturation and higher hypoxia tolerance in males. In juvenile Greenland halibut, exposure to chronic hypoxia elicited a more wide-ranging enzymatic response than did acute exposure to severe hypoxia. Under chronic hypoxia, CS activity decreased and PK and LDH activity were respectively 46% and 57% lower than in normoxia. There were no major changes in the activity of antioxidant enzymes, but activity in normoxia was high compared to other fish species. Interestingly, the relative expression of genes coding for muscle COX (severe hypoxia), liver PEPCK (chronic), and CAT (chronic) activities were triggered in hypoxia. The absence of a corresponding change in enzyme activity makes the interpretation of these results difficult, but clearly there was a response at the transcription level. Overall, the results indicate that these two species are particularly well adapted to withstand severe hypoxia. -- Keywords : Aerobic pathwa ; Anaerobic pathway ; Antioxidant defence ; Metabolic capacity ; Gene expression ; Enzyme activity.

Cooking is an important unit-operation in the production of cooked and peeled shrimps. The present study explores the feasibility of using ohmic heating for cooking of shrimps. The focus is on investigating the effects of different process parameters on heating time and quality of ohmic cooked shrimps ( Pandalus Borelias ). The shrimps were heated to a core temperature of 72 °C in a brine solution using a small batch ohmic heater. Three experiments were performed: 1) a comparative analyses of the temperature development between different sizes of shrimps and thickness (head and tail region of the shrimp) over varying salt concentrations (10 kg m −3 to 20 kg m −3 ) and electric field strengths (1150 V m −1 to 1725 V m −1 ) with the heating time as the response; 2) a 2 level factorial experiment for screening the impact of processing conditions using electric field strengths of 1250 V m −1 and 1580 V m −1 and salt concentrations of 13.75 kg m −3 and 25.75 kg m −3 and 3) evaluating the effect of pretreatment (maturation) of the shrimps before ohmic processing. The maturation experiment was performed with the following maturation pre-treatments: normal tap water, a 21.25 kg m −3 brine solution and without maturation. The measured responses for experiments 2 and 3 were: the heating time until the set temperature of the shrimps was reached, weight loss, press juice and texture profile. It was possible to fit main effects model relating process settings and the heating time, weight loss and press juice measurements. Furthermore, the results showed that over the tested process workspace no significant changes were seen in the texture measurements of the shrimps and that the shrimp achieved a comparable quality compared to the conventional heating processes reported in the literature. The findings show a promising utilization of ohmic heating as a unit operation for the shrimp processing industries.

P. lophotes Chace, 1985 Description. Rostrum remarkably curving dorsally, 1.5 times as long as carapace, dorsal margin with 14 teeth including 5���6 on carapace, all teeth on carapace with distinct basal sutures and movable, ventral margin with 13��� 18 teeth; abdomen smooth and rounded dorsally, pleura of fourth and fifth somites with small marginal tooth posteriorly sixth somite 1.5 times as long as maximum height; eye broadly subpyriform, maximum diameter about 0.2 carapace length; 3rd maxilliped overreaching distal margin of antennal scale by half of ultimate segment, with epipod, penultimate segment about 0.7 as long as ultimate segment; 2nd pereopods unequal with epipods, not extremely slender or thread-like, left overreaching antennal scale by distal 3 segment and anterior 0.3 of merus, with 147 carpal articles, right overreaching antennal scale by entire chela and anterior 0.7 of carpus, with 40 carpal articles (Kim et al. 2012). Distribution. Indo-West Pacific: Korea, Japan, Philippines, Vietnam and southern Arabia; at depths of 105��� 329 m (Kim et al. 2012)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 585, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411","Kim, J. N., Choi, J. H., Lee, J. H. & Kim, J. I. (2012) Six Pandalid Shrimps of the genus Plesionika (Crustacea: Decapoda: Caridea) in Korea. Animal Systematics, Evolution and Diversity, 28, 105 - 116."]}

P. unidens Bate, 1888 Description. Rostrum far overreaching antennal scale, armed dorsally with 7 or 8 teeth, including 3 on carapace posterior to level of orbital margin and 1 isolated in anterior 1/4 of rostrum, 3 posteriormost teeth with distinct basal sutures but none with barbed tips, armed ventrally with 10���20 teeth; abdomen with 3rd somite lacking posteromesial tooth but with median dorsal carina typically forming obtuse tooth anterior to posterior margin of somite; eye kidney-shaped, maximum diameter about 1/3 carapace length, ocellus obliquely oval, slightly constricted at junction with cornea; 3rd maxilliped with epipod, penultimate segment about 4/5 as long as terminal segment; 2nd pereopods very unequal with epipods, left one longer with more than 200 carpal articles, right with 33���36 (Chace 1985). Distribution. Bay of Bengal, South and East China seas, Japan, Philippines and Indonesia; at depths of 184��� 400m (Li 2006b)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 589, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411","Li, X. (2006 b) Report on some pandalid shrimps from the East China Sea (Decapoda, Caridea). Crustaceana, 79, 1281 - 1296. https: // doi. org / 10.1163 / 156854006779277303"]}

P. sindoi (Rathbun, 1906) Description. Rostrum 1.5 times as long as carapace, from the orbital margin the rostrum runs horizontally forward as far as the distal extremity of the antennular peduncle and from here it is a little and obliquely turned upward, 5 movable teeth on the carapace, lower margin is armed with 6 teeth; abdomen nearly 4-times as long as the carapace; the eyes are little more than one-fourth the length of the carapace and this diameter is slightly longer than the axial; external maxillipeds reach by their terminal joint and one-fourth of the penultimate beyond the antennal scale, exopodite small, not yet reaching to the middle of the antepenultimate joint; 1st pereopods reach by 4/5 their terminal joint (or propodus) beyond the external maxillepeds the penultimate joint or carpus is almost twice as long as the terminal, these joints being respectively 9.1 mm. and 5 mm. long in the adult female (Chace1985). Distribution. Japan, South China Sea, Philippines and Indonesia; at depths of 122���800 m (Li & Komai 2003)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 588, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411","Li, X. & Komai, T. (2003) Pandaloid shrimps from the northern South China Sea, with description of a new species of Plesionika (Crustacea: Decapoda: Caridea). Raffles Bulletin of Zoology, 51, 257 - 275."]}

P. alcocki (Anderson, 1896) Description. The rostrum is nearly 1.5 to 2.0 times of the carapace length, it is armed dorsally at its basal end with usually 5 teeth, three or four of which are movable and very small and stand close together on the gastric crest, with two large isolated ones just in front of them, ventrally it is armed throughout, beyond the antennular peduncle, with a series of distant teeth not concealed by setae to the number of from 4 to 8; the 6th abdominal tergum is not quite twice as long as the 5th; there is no distinct ocellus on the dorsal margin of the eye; 1st perepods are not shorter than the external maxillipeds, 2nd perepods in the male alone are very slightly unequal in length: one of them reaches almost to the other very slightly beyond the tips of the external maxillipeds (Alcock 1901). Distribution. Arabian Sea, off the south and south-west coast of India, Bay of Bengal, Andaman Sea, Indonesia, Japan and Philippines; at depths of 496���1092 m (Alcock 1901; Holthuis 1980; De Grave & Fransen 2011)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 580, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Alcock, A. (1901) A descriptive catalogue of Indian deep - sea Crustacea, Decapoda, Macrura and Anomala in the Indian Museum., Baptist Mission Press, Calcutta, India, 286 pp.","Holthuis, L. B. (1980) Shrimps and prawns of the world. An annotated catalogue of species of interest to fisheries. FAO Species Catalogue, Vol. 1. FAO Fisheries Synopsis, 125, 1 - 271.","DeGrave, S. & Fransen C. H. J. M. (2011) Carideorum Catalogus: the recent species of the dendrobranchiate, stenopodidean, procarididean and caridean shrimps (Crustacea: Decapoda). Zoologische Mededelingen, Leiden, 89, 195 - 589."]}

P. longidactylus Li & Komai, 2003 Description. Rostrum far overreaching antennal scale, 1.1–1.2 times as long as carapace, armed dorsally with 5 moderately large teeth, each with obscurely barbed tip and with 2 tiny subapical teeth, ventral margin with 10–13 teeth; 3rd abdominal somite not compressed dorsally, unarmed on posterodorsal margin; 3rd maxilliped with ultimate segment about 1.4 times as long as penultimate segment; 2nd pereopods greatly unequal with well developed strap-like epipod each bearing terminal hook, left with 25–30 carpal articles and right with 8 carpal articles (Li & Komai 2003). Distribution. Known only from South China Sea at depths of 55–144 m (Li 2006a).

P. heterocarpus (Costa, 1871) Description. Rostrum long, about two times as long as scaphopcerite, slender and slightly curved upward, dorsal margin with 15���23 teeth of which the proximal 4���6 are movable and situated behind the orbit, ventral margin bears 16���23 teeth; posterior part of the 3rd abdominal somite is slightly concave; eye with maximum diameter about l/5 of carapace length, ocellus longitudinally oval, constricted at juncture with cornea; 3rd maxilliped with well developed strap-like epipod, penultimate segment sub-equal to terminal segment; 2nd pair of pereiopod distinctly unequal, left one much longer than the right one, overreaching scaphocerite with chela, carpus and distal half of merus, with 107���215 carpal segments, 80���111 meral segments and about 25 ischial segments (Holthuis 1980). Distribution. Cyprus, Israel, Syria and Turkey; at depths of 10���850 m (Holthuis 1980)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 583, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Holthuis, L. B. (1980) Shrimps and prawns of the world. An annotated catalogue of species of interest to fisheries. FAO Species Catalogue, Vol. 1. FAO Fisheries Synopsis, 125, 1 - 271."]}

P. hypanodon Doflein, 1902 Description. Rostrum is only half as long as the carapace and quite straight, except for the tip, which is bent upwards, dorsal margin with 7 teeth, the anterior three are behind the eye basis, smaller and stand narrower to each other than the other 4, which are arranged in similar distances towards the tip, ventral margin is smooth and without teeth; abdomen is smooth, compressed, and the hindmargin of the third segment is slightly recessed; eyes are spherical-shaped, semi-large with distinct ocellus; 2nd pereiopods equally long and slender with 15 carpal articles (Doflein 1902). Distribution. Known only from Sagami Bay, Japan (Doflein 1902)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 583, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Doflein, F. (1902) Ostasiatische Dekapoden. Abhandlungen der Bayerischen Akademie der Wissenschaften, Munchen, 21, 613 - 670."]}

P. hsuehyui Chan, 2004 Description. Rostrum 1.3���2.0 times as long as carapace, bending downwards near base but recurved upwards after passing eyes, dorsal rostrum proper unarmed except for 2 small subapical teeth, ventral rostrum generally bearing 9 or 10 teeth; abdominal 3rd somite slightly arched dorsally; 3rd maxilliped overreaching scaphocerite by up to 2/3 length of distal segment, distal segment 1.4���1.8 times as long as penultimate segment; 2nd pereopods bearing 15��� 22 carpal articles on right side and 53���70 carpal articles on left side, shorter one exceeding scaphocerite by about half chela (Chan 2004). Distribution. Taiwan and Philippines; at depths of 115���300 m (Chan 2004)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 583, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chan, T. Y. (2004) The \" Plesionika rostricrescentis (Bate, 1888) \" and \" P. lophotes Chace, 1985 \" species groups of Plesionika Bate, 1888, with descriptions of five new species (Crustacea: Decapoda: Pandalidae), in Marshall B. & Richer De Forges B. (eds), Tropical deep-sea benthos, vol. 23. Memoires du Museum national d'Histoire naturelle, Paris, 191, 293 - 318."]}

P. taiwanica Chan & Yu, 2000 Description. Rostrum 1.3–2.1 times as long as carapace, slightly curving downward at basal part but gently recurved upwards and straight after passing antennular peduncle, dorsal border generally armed with 6–8 teeth, with posterior 4–6 teeth restricted at basal part and forming a low crest while the anterior 1–3 teeth located anterior to level of antennular peduncle, lower border densely serrated with 22–38 small teeth; abdominal 3rd somite feebly arched dorsally and with posterior margin convex; eye subspherical and probably bearing indistinct ocellus; 3rd maxilliped bearing well developed epipod and long strip-like exopod, penultimate segment 1.2–1.5 times as long as distal segment, overreaching scaphocerite by 1/3 to almost entire distal segment; 2nd pereiopods subequal with well developed epipod, bearing 16–25 carpal articles (Chan & Yu 2000). Distribution. Known only from Taiwan at depths of 150–300 m (Chan & Yu 2000).

P. taiwanica Chan & Yu, 2000 Description. Rostrum 1.3���2.1 times as long as carapace, slightly curving downward at basal part but gently recurved upwards and straight after passing antennular peduncle, dorsal border generally armed with 6���8 teeth, with posterior 4���6 teeth restricted at basal part and forming a low crest while the anterior 1���3 teeth located anterior to level of antennular peduncle, lower border densely serrated with 22���38 small teeth; abdominal 3rd somite feebly arched dorsally and with posterior margin convex; eye subspherical and probably bearing indistinct ocellus; 3rd maxilliped bearing well developed epipod and long strip-like exopod, penultimate segment 1.2���1.5 times as long as distal segment, overreaching scaphocerite by 1/3 to almost entire distal segment; 2nd pereiopods subequal with well developed epipod, bearing 16���25 carpal articles (Chan & Yu 2000). Distribution. Known only from Taiwan at depths of 150���300 m (Chan & Yu 2000)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 589, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chan, T. Y. & Yu H. P. (2000) A new deep - sea shrimp of the genus Plesionika Bate, 1888 (Crustacea: Decapoda: Pandalidae) from Taiwan. National Taiwan Museum Special Publication Series, 10, 119 - 127."]}

P. edwardsii (Brandt, 1851) Description. Rostrum curved downward in basal region, then strongly curved upwards beyond antennular peduncle, slightly more than 2 times as long as carapace, armed dorsally with 28���36 teeth over entire length, anterior teeth closely spaced, posterior teeth larger and well spaced, ventral border bearing 37���52 closely spaced teeth; dorsal surface of abdominal 3rd somite slightly arched but not sharply angular; eye large and subspherical, with distinct ocellus; 3rd maxilliped with distal two segments subequal, bearing rudimentary epipod; 2nd Pereiopods subequal with 18���28 carpal articles (Chace 1985). Distribution. Indo-Pacific, Indonesia, Philippines and Taiwan; at depths of 50���680 m (Chace 1985). P. ensis (Milne-Edwards, 1881) Description. Rostrum nearly 1.6 to 2 times of the carapace length, armed dorsally with 5 or 6 teeth, three or four close together, two isolated anteriorly, ventrally it is closely and evenly serrated, the teeth are fixed; the posterior border of the 3rd abdominal tergum is acutely produced in the middle line to form a spine; the ocellus is distinct but not independent; the external maxillipeds with well-developed exopodite, little longer and stouter than the 1st pair of pereopods, reach a short way beyond the tip of the antennal scale (Alcock 1901). Distribution. Arabian Sea, Bay of Bengal and Andaman Sea; at depths of 250���400 m (Alcock 1901)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 582, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411","Alcock, A. (1901) A descriptive catalogue of Indian deep - sea Crustacea, Decapoda, Macrura and Anomala in the Indian Museum., Baptist Mission Press, Calcutta, India, 286 pp."]}

P. spinensis Chace, 1985 Description. Rostrum far overreaching antennal scale, armed dorsally throughout length with 13���24 teeth, including 2 or 3 on carapace posterior to level of orbital margin, posteriormost tooth with faint, incomplete basal suture, none with barbed tips, armed ventrally with 2539 teeth; abdomen typically with posteromesial tooth but without median dorsal carina on 3rd somite; eye very broadly subpyriform, maximum diameter nearly or quite 1/3 carapace length, ocellus subcircular, somewhat constricted at juncture with cornea; 3rd maxilliped with epipod, penultimate segment slightly shorter or longer than terminal segment; 2nd pereopods subequal with welldeveloped epipod, bearing 14���23 carpal articles (Chace 1985). Distribution. South China Sea and Philippines; at depths of 199���472 m (Li 2006a), Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 588, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411","Li, X. (2006 a) Additional Pandalid shrimps from the South China Sea (Crustacea: Decapoda: Caridea), with description of a new species. Raffles Bulletin of Zoology, 54, 361 - 372."]}

P. longidactylus Li & Komai, 2003 Description. Rostrum far overreaching antennal scale, 1.1���1.2 times as long as carapace, armed dorsally with 5 moderately large teeth, each with obscurely barbed tip and with 2 tiny subapical teeth, ventral margin with 10���13 teeth; 3rd abdominal somite not compressed dorsally, unarmed on posterodorsal margin; 3rd maxilliped with ultimate segment about 1.4 times as long as penultimate segment; 2nd pereopods greatly unequal with well developed strap-like epipod each bearing terminal hook, left with 25���30 carpal articles and right with 8 carpal articles (Li & Komai 2003). Distribution. Known only from South China Sea at depths of 55���144 m (Li 2006a)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on pages 584-585, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Li, X. & Komai, T. (2003) Pandaloid shrimps from the northern South China Sea, with description of a new species of Plesionika (Crustacea: Decapoda: Caridea). Raffles Bulletin of Zoology, 51, 257 - 275.","Li, X. (2006 a) Additional Pandalid shrimps from the South China Sea (Crustacea: Decapoda: Caridea), with description of a new species. Raffles Bulletin of Zoology, 54, 361 - 372."]}

P. indica De Man, 1917 Description. Rostrum 1.8 times as long as carapace, far overreaching antennal scale, armed dorsally throughout length with 27���33 teeth, including 4���6 on carapace posterior to level of orbital margin, 2���4 posteriormost teeth with distinct basal suture but none with barbed tips, armed ventrally with 22���27 teeth; abdomen without posteromesial tooth or median dorsal carina on 3rd somite; eye subpyriform, maximum diameter fully 1/6 carapace length, ocellus prominent, somewhat constricted at juncture with cornea; 3rd maxilliped with epipod, penultimate segment 1.2���1.4 times as long as terminal segment; 2nd pereopods subequal with prominent epipods, bearing 31��� 34 carpal articles (De Man 1920; Chace 1985). Distribution. Indonesia, South China Sea, Philippines and Japan; at depths of 238��� 472 m. (Li & Komai 2003)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 583, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411","Li, X. & Komai, T. (2003) Pandaloid shrimps from the northern South China Sea, with description of a new species of Plesionika (Crustacea: Decapoda: Caridea). Raffles Bulletin of Zoology, 51, 257 - 275."]}

P. spinidorsalis (Rathbun, 1906) Description. Rostrum overreaching antennal scale, armed dorsally throughout length with 12���15 teeth, including 7���10 on carapace posterior to level of orbital margin, none with basal suture or barbed tip, armed ventrally with 4��� 8 teeth; orbital margin with subquadrate lobe, thence trending posterodorsally in nearly straight line and, finally, bending sharply anterodorsally at extreme dorsal limit; abdomen without posteromesial tooth or median dorsal carina on 3rd somite; eye pyriform, maximum diameter about 1/8 carapace length, without ocellus; 3rd maxilliped with epipod, penultimate segment slightly more than 1/2 to 2/3 as long as terminal segment; 2nd pereopods unequal and dissimilar with epipod, right one shorter, more robust, and with 5 or 6 carpal articles, left one with 13��� 16 carpal articles (Chace 1985). Distribution. South China Sea, Philippines and Indonesia; at depths of 100���1250 m (Li 2006a)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 589, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411","Li, X. (2006 a) Additional Pandalid shrimps from the South China Sea (Crustacea: Decapoda: Caridea), with description of a new species. Raffles Bulletin of Zoology, 54, 361 - 372."]}

P. fimbriata Chace, 1985 Description. Rostrum far overreaching antennal scale, armed dorsally throughout length with 11���14 teeth, including 3 or 4 on carapace posterior to level of orbital margin, 2���4 posteriormost teeth with distinct basal sutures but none with barbed tips, armed ventrally with 5���8 teeth; abdomen without posteromesial tooth or median dorsal carina on 3rd somite; eye broadly subpyriform, maximum diameter about one-fourth carapace length, ocellus large, subcircular, in broad contact with cornea; 3rd maxilliped with epipod, penultimate segment 1.2���1.5 times as long as terminal segment; 2nd peropods subequal with epipod, bearing 18���30 carpal articles (Chace 1985). Distribution. Known only from the Philippines at depths of 95���250 m (Chace 1985)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 582, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chace, F. A. Jr. (1985) The caridean shrimps (Crustcea: Decapoda) of the Albatross Philippine Expedition, 1907 - 1910, Part 3: Families Thalassocarididae and Pandalidae. Smithsonian Contributions to Zoology, 411, 1 - 143. https: // doi. org / 10.5479 / si. 00810282.411"]}

P. erythrocyclus Chan & Crosnier, 1997 Description. Rostrum more or less as long as carapace and just overreaching scaphocerite, curving downward at base but abruptly upturned after passing the eye, dorsal border with only 2 small apical teeth and 1���2 fixed basal teeth above eye, ventral border with 7���9 evenly distributed teeth between level of eye and tip; eye subspherical and bearing distinct ocellus; 3rd maxilliped bearing well developed epipod and a long exopod, with penultimate segment 0.6���0.7 times as long as distal segment, overreaching scaphocerite by 1/3���1/2 of distal segment; 2nd pereiopods bearing 20���22 carpal articles on the right side and 76���83 carpal articles on the left side (Chan & Crosnier 1997). Distribution. Known only from Taiwan at depths of 267���360 m (Chan 2004)., Published as part of Ahamed, Ferdous, Cardoso, Irene A., Ahmed, Zoarder F., Hossain, Md. Y. & Ohtomi, Jun, 2017, An overview of the genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in Asian waters, pp. 575-593 in Zootaxa 4221 (5) on page 582, DOI: 10.11646/zootaxa.4221.5.6, http://zenodo.org/record/253575, {"references":["Chan, T. Y. & Crosnier, A. (1997) Crustacea Decapoda: deep - sea shrimps of the genus Plesionika Bate, 1888 (Pandalidae) from French Polynesia, with descriptions of five new species. In: A. Crosnier (ed.), Resultats des Campagnes MUSORSTOM, 18. Memoires du Museum national d'Histoire naturelle, Paris, (A) 176, 187 - 234.","Chan, T. Y. (2004) The \" Plesionika rostricrescentis (Bate, 1888) \" and \" P. lophotes Chace, 1985 \" species groups of Plesionika Bate, 1888, with descriptions of five new species (Crustacea: Decapoda: Pandalidae), in Marshall B. & Richer De Forges B. (eds), Tropical deep-sea benthos, vol. 23. Memoires du Museum national d'Histoire naturelle, Paris, 191, 293 - 318."]}

P. erythrocyclus Chan & Crosnier, 1997 Description. Rostrum more or less as long as carapace and just overreaching scaphocerite, curving downward at base but abruptly upturned after passing the eye, dorsal border with only 2 small apical teeth and 1–2 fixed basal teeth above eye, ventral border with 7–9 evenly distributed teeth between level of eye and tip; eye subspherical and bearing distinct ocellus; 3rd maxilliped bearing well developed epipod and a long exopod, with penultimate segment 0.6–0.7 times as long as distal segment, overreaching scaphocerite by 1/3–1/2 of distal segment; 2nd pereiopods bearing 20–22 carpal articles on the right side and 76–83 carpal articles on the left side (Chan & Crosnier 1997). Distribution. Known only from Taiwan at depths of 267–360 m (Chan 2004).

The morphology of the decapodid stage of Plesionika narval (Fabricius, 1787) is described and illustrated based on larvae collected in the Canary Islands waters (NW Africa). Mitochondrial DNA analysis of the barcoding gene COI sequences confirmed the identity of the larvae specimens. Decapodid development of P. narval is compared with other pandalid and related genera Pandalus, Pandalopsis, Procletes, Stylopandalus, and Icotopus. Based on their morphological similarities we concluded that the nomina dubia genus Icotopus is a synonym of Plesionika and herein selected Plesionika over Icotopus as the valid name for the genus.

We examined spatial and temporal relationships between snow crab Chionocetes opilio, shrimp Pandalus spp., Atlantic cod Gadus morhua and the environment (depth, tempera- ture and salinity) on the Newfoundland-Labrador Shelf from 1995 to 2009 using autumn multi- species trawl survey data. First, the core habitat of snow crab and shrimp was determined based on cumulative distribution functions of species abundance over depth and bottom temperature. On average, this method predicted the presence of crab and shrimp at 95 and 99% of trawl loca- tions, respectively, and indicated 90% of crab and shrimp inhabited temperature ranges of �1 to 4 and 0 to 4°C and depths of 100 to 500 and 150 to 450 m, respectively. Then geographically weighted regressions, based on trawl stations where species presence was predicted, indicated spatial non-stationarity between invertebrates and explanatory variables at scales

Two trawl gear modifications for reducing fish bycatch (weight) in ocean shrimp ( Pandalus jordani ) trawls were tested in June and August–September 2010. The primary focus of the study was evaluating trawl system modifications for reducing bycatch of eulachon ( Thaleichthys pacificus ) below levels already achieved via mandatory use of bycatch reduction devices (BRDs). An experimental footrope, modified by removing the central one third of the trawl groundline, reduced eulachon bycatch by 33.9%. It also reduced bycatch of slender sole ( Lyopsetta exilis ), other small flatfishes and juvenile darkblotched rockfish ( Sebastes crameri ) by 80% or more, but had no effect on bycatch of whitebait smelt ( Allosmerus elongatus ) or Pacific herring ( Clupea pallasii ). The experimental groundline also reduced the catch of ocean shrimp (weight) by 22.2% in hauls yielding commercial quantities of shrimp (>194 kg/haul) and by 23.2% in all hauls. Reducing bar spacing in a rigid-grate BRD from 25.4 mm to 19.1 mm reduced eulachon bycatch by 16.6%, with no reduction in ocean shrimp catch. It also reduced bycatch of slender sole, other small flatfish and juvenile darkblotched rockfish by 36.8%, 71.8% and 76.3%, respectively with no effect on bycatch of whitebait smelt or young-of-the-year (YOY) Pacific hake ( Merluccius productus ). Although both trawl modifications reduced eulachon bycatch, the footrope modification tested, if developed further, has the potential to also avoid trawl entrainment for some demersal fishes, as well as reduce bottom impacts from trawling.

The population dynamics of Pandalus gracilis was investigated in the southeastern coastal area of Korea between May 1998 and April 2000. Of the 4,127 specimens, 57% were identified as females, 39% as males, and 4% as transitional hermaphrodites. The number of females was greater than that of males and transexuals. A significant correlation was observed between the number of transitional hermaphrodites and ambient seawater temperature. Growth parameters were estimated using the modified von Bertalanffy growth function model incorporating seasonal variation in growth using the program ELEFAN. Females grew faster and reached a larger sizeat-age than males (K=0.65/y and L∞=17.86 mm carapace length [CL] for females; K=0.51/y and L∞=14.70 mm CL for males). Mean size and age (95% confidence limits) at sex transition, calculated from growth parameters, were 7.07 mm carapace length and 1.05 years, respectively. The reproductive strategies of pandalid shrimps are discussed in terms of the type of sex transition.

Vitellogenin (Vg) is the precursor of vitellin (Vn), which is the major yolk protein in nearly all oviparous species, including fish, amphibians, reptiles, and most invertebrates. It is one of the most important factors during reproduction, and numerous studies have shown that Vg genes are markers of the reproductive cycle and effecter genes induced by endocrine-disrupting chemicals (EDCs). Previously, we isolated two distinct cDNAs encoding vitellogenin homologs Pj-Vg1 and Pj-Vg2 from Pandalus shrimp Pandalopsis japonica. In this study, full-length genomic sequences of Pj-Vg1 and Pj-Vg2 were determined using a PCR-based genome walking strategy. Isolated Pj-Vg1 and Pj-Vg2 genes were 11,910 and 11,850 bp long, respectively. Both Pj-Vg genes had 15 exons and 14 introns, and the splicing sites were also the same, suggesting that they arose via gene duplication. The similar structural characteristics of decapod Vg genes suggest that they are all orthologs that evolved from the same ancestral gene. Analysis of Pj-Vg1 and Pj-Vg2 expression revealed that the relative copy numbers of Pj-Vg1 and Pj-Vg2 were similar in the hepatopancreas, whereas Pj-Vg2 transcripts were also detected in the ovary. Expression of both Pj-Vg genes was induced in hepatopancreas of mature individuals, whereas only Pj-Vg2 transcripts were upregulated in the ovaries from mature animals, suggesting that both Pj-Vgs are important for oocyte development. A strong positive correlation was found between Pj-Vg1 and Pj-Vg2 transcripts in the same individual, indicating they are under the same control mechanisms. Additionally, a positive correlation was found between ovarian and hepatopancreatic Pj-Vg2 transcripts, suggesting that its dual expression is regulated by similar physiological conditions. Knowledge of the similarities and differences between the two vitellogenin-like genes, Pj-Vg1 and Pj-Vg2, would help us to understand their roles in reproduction and other physiological effects.

The Northwest Atlantic marine community underwent dramatic changes during the last 30 years, including the collapse of many groundfish stocks and an increase in shrimp populations. Greenland halibut Reinhardtius hippoglossoides is an important commercial species and one of the top fish predators in this system. It is a large, wide-ranging flatfish that is found at depths up to 2200 m and it has an opportunistic diet which makes it a potential candidate for an ecosystem indicator. Analysis of stomach contents of Greenland halibut between 1978 and 2003 indicates that diet composition reflects the major changes in community structure. Over the entire period there was a clear increase in the importance of invertebrates, particularly after 1992. This change was associated with a higher importance of Pandalus shrimp and Gonatus squid and a protracted reliance on zooplankton by predators under 25 cm length. Capelin Mallotus villosus was the dominant prey between 1978 and 1992 for predators in the 12–63 cm range, but its importance dropped off drastically in the mid 1990s. Levels of main prey in the diet of Greenland halibut correlated well with fishery-independent surveys. Greenland halibut sample capelin well, compared to bottom trawl surveys and acoustic surveys. Greenland halibut consumed small shrimp which are not routinely caught by surveys and may be important in deriving information on year classes and growth of shrimp. Our results suggest that Greenland halibut's diet is a useful tracker of ecosystem change.

Eigaard, O. R., and Munch-Petersen, S. 2011. Influence of fleet renewal and trawl development on landings per unit effort of the Danish northern shrimp (Pandalus borealis) fishery. – ICES Journal of Marine Science, 68: 26–31. Recent stock assessments of the Pandalus stock in the Skagerrak (ICES Division IIIa) and the Norwegian Deep (Division IVa east) have relied largely on a time-series of landings per unit effort (lpue) calculated from Danish logbook data. Because of fleet renewal and trawl-size changes, the relationship between nominal effort data as recorded in logbooks (days fishing) and effective effort is likely to have changed, so to standardize the nominal lpue time-series, trawl-size development has been taken into account using generalized linear modelling. As logbooks do not provide trawl-size information, this standardization was made possible by retrieving technical trawl and vessel data from industry order books. These data demonstrated an approximately linear relationship between vessel engine power and Pandalus trawl size, so validated the use of vessel horsepower from the logbooks as a proxy for an unknown trawl size. Standardized lpue time-series for the past 20 years indicated a lesser increase in stock size than nominal lpue, the modelling results demonstrating that vessel lpue increased by 9.5% with each 100 hp of engine power.

Endosulfan is a neurotoxic organochlorine insecticide of the cyclodiene family of pesticides that inhibits molting and reproduction in aquatic crustaceans. In order to determine the molecular mechanism of endosulfan as an endocrine disrupting chemical (EDC), differential display RT-PCR (DDRT-PCR) was used to isolate genes in the shrimp, Pandalopsis japonica , affected by endosulfan exposure. PCR screening of cDNA from the hepatopancreas from control and endosulfan-exposed animals, using 120 sets of random primers, yielded partial cDNAs encoding two vitellogenin-like proteins (Pj-Vg1 and -Vg2). Complete sequences were obtained using a combination of RT-PCR and RACE-PCR. Pj-Vg1 (7883 bp) encoded a protein composed of 2533 amino acid residues (283.27 kDa estimated mass), whereas Pj-Vg2 (7792 bp) encoded a protein composed of 2537 amino acids residues (284.87 kDa estimated mass). Alignment of the Pj-Vgs with those of other vitellogenins identified a conserved subtilisin cleavage site (RQKR) and the lipoprotein N-terminal (vitellin), DUF1081, and von Willebrand factor type D domains, indicating both genes encoded functional proteins. Phylogenetic analysis showed that Pj-Vg1 and -Vg2 were most similar to Pandalus hypsinotus Vg. Both Pj-Vg1 and -Vg2 were expressed primarily in the hepatopancreas, although the Pj-Vg2 transcript was also detected in the ovary. The effects of the 3-day endosulfan exposure (2.5 µg/L and 25 µg/L) on Vg expression in the hepatopancreas were determined by quantitative RT-PCR. Expression of both transcripts was significantly inhibited at 25 µg/L suggesting that Pj-Vgs can be used as indicator for endosulfan exposure.

The spot prawn (Pandalus platyceros) trap fishery in British Columbia is endorsed by conservation organizations owing to the assumption of minimal bycatch. However, reported capture of juvenile rockfish (Sebastes spp.) in prawn traps has raised concern due to declines in abundance of many rockfish stocks. We document the bycatch observed in a 10-year (1999–2008) fishery-independent research survey that employed traps that are similar to the traps used in the commercial spot prawn fishery. Research traps produced 0.16–0.20 kg of non-target catch per kg of spot prawn catch, with bycatch consisting mainly of a variety of molluscs, non-target crustaceans, echinoderms, and fish. The overall rate of rockfish catch was low—0.015 rockfish per trap. The annual rate of rockfish bycatch has increased since 2004, to 0.039 rockfish per trap in 2008, while catch rates of other species have remained relatively constant. Our results confirm that spot prawn traps produce a low amount of bycatch by weight. However, they also suggest that rockfish mortality due to prawn trapping should be quantified in the commercial prawn fishery to determine how this source of mortality may affect rockfish stocks. Furthermore, research into bycatch reduction technology to improve trap selectivity, and thus reduce rockfish bycatch, would be desirable.

[The population dynamics of Pandalus gracilis were investigated in the southeast coastal area of Korea, between May 1998 and April 2000. The number of females was greater than that of males and of intersexes. Based on dry weight of egg masses at the early stage, the reproductive output averaged 34% of female weight. A higher gonadosomatic index (GSI) was observed from December to June. Ovigerous females occurred from December to September. During the incubation period, the egg volume significantly increased and brood loss of eggs occurred. A significant difference in ovarian weight between females with early eggs and late egg stages was found. This indicates that ovarian maturation occurs during the incubation time, suggesting that females are potentially consecutive breeders, capable of multiple spawnings during a reproductive season. Spawning by a single female seems to occur consecutively in a single reproductive period. Female maturity was determined by the frequency of both ovigerous females and females with a maturing ovary. The size at 50% sexual maturity (CL50) was estimated as 9.2 mm. The size distribution in the population was similar in the two years of this study. La dynamique des populations de Pandalus gracilis a ete etudiee dans la zone cotiere sudorientale de la Coree, entre mai 1998 et avril 2000. Le nombre de femelles etait plus eleve que celui des mâles et des animaux intersexues. A partir du poids sec des oeufs au premier stade, la production etait en moyenne 34% du poids de la femelle. Un index gonado-somatique (GSI) plus eleve a ete observe de decembre a juin. Les femelles ovigeres etaient presentes de decembre a septembre. Au cours de la periode d'incubation, le volume de l'œuf augmentait significativement et la perte des œufs a ete observee. Une difference significative du poids de l'ovaire entre femelles a œufs aux premiers stades et femelles a œufs plus avances a ete trouvee. Ceci indique que la maturation de l'ovaire intervient pendant la periode d'incubation, suggerant que les femelles ont potentiellement des productions d'œufs successives, et sont capables de pontes multiples au cours d'une saison de reproduction. La ponte chez une femelle semble se produire plusieurs fois a la suite au cours d'une periode de reproduction. La maturite de la femelle etait determinee par la frequence a la fois des femelles ovigeres et des femelles presentant un ovaire en cours de maturation. La taille a 50% de maturite sexuelle, (CL50) a ete estimee a 9,2 mm. La distribution de taille dans la population etait analogue au long des deux annees qu'a dure cette etude., The population dynamics of Pandalus gracilis were investigated in the southeast coastal area of Korea, between May 1998 and April 2000. The number of females was greater than that of males and of intersexes. Based on dry weight of egg masses at the early stage, the reproductive output averaged 34% of female weight. A higher gonadosomatic index (GSI) was observed from December to June. Ovigerous females occurred from December to September. During the incubation period, the egg volume significantly increased and brood loss of eggs occurred. A significant difference in ovarian weight between females with early eggs and late egg stages was found. This indicates that ovarian maturation occurs during the incubation time, suggesting that females are potentially consecutive breeders, capable of multiple spawnings during a reproductive season. Spawning by a single female seems to occur consecutively in a single reproductive period. Female maturity was determined by the frequency of both ovigerous females and females with a maturing ovary. The size at 50% sexual maturity (CL50) was estimated as 9.2 mm. The size distribution in the population was similar in the two years of this study. La dynamique des populations de Pandalus gracilis a ete etudiee dans la zone cotiere sudorientale de la Coree, entre mai 1998 et avril 2000. Le nombre de femelles etait plus eleve que celui des mâles et des animaux intersexues. A partir du poids sec des oeufs au premier stade, la production etait en moyenne 34% du poids de la femelle. Un index gonado-somatique (GSI) plus eleve a ete observe de decembre a juin. Les femelles ovigeres etaient presentes de decembre a septembre. Au cours de la periode d'incubation, le volume de l'œuf augmentait significativement et la perte des œufs a ete observee. Une difference significative du poids de l'ovaire entre femelles a œufs aux premiers stades et femelles a œufs plus avances a ete trouvee. Ceci indique que la maturation de l'ovaire intervient pendant la periode d'incubation, suggerant que les femelles ont potentiellement des productions d'œufs successives, et sont capables de pontes multiples au cours d'une saison de reproduction. La ponte chez une femelle semble se produire plusieurs fois a la suite au cours d'une periode de reproduction. La maturite de la femelle etait determinee par la frequence a la fois des femelles ovigeres et des femelles presentant un ovaire en cours de maturation. La taille a 50% de maturite sexuelle, (CL50) a ete estimee a 9,2 mm. La distribution de taille dans la population etait analogue au long des deux annees qu'a dure cette etude.]

The concentrations of Fe, Zn, Cu, Cd, Mn, Pb, and Ni were determined in the hepatopancreas, muscle tissue, and carapace of the grass shrimp Pandalus kessleri from the coastal waters of the Lesser Kurilskaya Ridge. Sex reversal of the grass shrimp, which is a proterandrous hermaphrodite, had a marked influence on the concentrations of such metals as Fe, Cu, Cd, and Mn. The levels of Cd in the hepatopancreas of grass shrimp exceeded maximum permissible concentrations for seafood at all the stations studied. The main factors determining the metal levels in P. kessleri from the investigated locations are discussed.

The family Pandalidae has a cosmopolitan distribution, occurring from the coastal region to more than 3000 meters of depth, and includes some species of economic importance. Three genera occur from Brazil: Heterocarpus A. Milne Edwards, 1881, Plesionika Bate, 1888 and Pandalus Leach, 1814. During the collections of the Programa de Avaliação dos Recursos Vivos da Zona Econômica Exclusiva of Brazil (REVIZEE, Northeast Score) a male of Heterocarpus laevigatus was collected in Pernambuco State, at a depth of 500m and fourteen females and four males of Plesionika escatilis were collected off the States of Pernambuco, Alagoas and Bahia, in depths varying from 93 to 260m. These records supplement the information on the distribution of these species, and represent the first records of H. laevigatus and P. escatilis from the Atlantic coast of South America.

The requirement, in 2003, that trawl vessels fishing for ocean shrimp (Pandalus jordani) use bycatch reduction devices (BRDs) has reduced fish bycatch by between 66% and 88% from historical (pre-BRD) levels. Prior to BRD requirements, bycatch was composed by weight mostly of adult and juvenile Pacific hake (Merluccius productus), various smelts (Osmeridae), yellowtail rockfish (Sebastes flavidus), sablefish (Anoplopoma fimbria) and lingcod (Ophiodon elongatus) and ranged from 32% to 61% of the total catch by weight. By 2005, BRD use had reduced fish bycatch to approximately 7.5% of total catch, composed mostly of juvenile Pacific hake, slender sole (Eopsetta exilis), smelts, rex sole (Errex zachirus) and juvenile rockfish (Sebastes). BRD requirements have eliminated marketable-sized fish from the catch, changing the economic incentives in the fishery to favor the use of more efficient BRDs. Based on Oregon data, from 2002 to 2005 the use of soft-panel BRDs declined and the use of more efficient rigid-grate BRDs increased to 97% of all trips. Over this same period, mean bar spacing in rigid-grate BRDs declined from 43 to 32 mm, also contributing to BRD efficiency. Data collected from a trawl experiment testing a rigid-grate BRD with 19-mm bar spacing suggest that bycatch in the ocean shrimp fishery can be reduced further, perhaps below 5% of total catch.

The present paper reports on four species of pandalid shrimp from the Yellow Sea: Pandalus gracilis Stimpson, 1860, Pandalus prensor Stimpson, 1860, Plesionika izumiae Omori, 1971, and Procletes levicarina (Bate, 1888). Pandalus prensor and Procletes levicarina are now recorded with certainty from the Yellow Sea for the first time.

The present paper reports 15 species of pandalid shrimp from the East China Sea, including an undescribed species of Plesionika represented by a damaged, ovigerous female specimen. This Plesionika sp. is closely similar to forms of the "Plesionika rostricrescentis" group. It can be distinguished readily from other members of the group by the greater number of ventral rostral teeth, which are set more closely, the low basal rostral crest, and the short stylocerite, which does not project beyond the end of the first segment of the antennular peduncle. Besides this Plesionika sp., the following species are reported for the first time from the East China Sea: Heterocarpus woodmasoni Alcock, 1901, Pandalus gracilis Stimpson, 1860, Plesionika orientalis Chace, 1985, Plesionika reflexa Chace, 1985, Plesionika sindoi (Rathbun, 1906), and Plesionika unidens Bate, 1888.

Most pandalid shrimps show protandric hermaphroditism, and male sexual differentiation is considered to be controlled by the androgenic gland. In the present study, we examined the histology of gonadal development during the male phase and sex change and the involvement of the androgenic gland in regulating male reproduction in laboratory-maintained Pandalus hypsinotus. Juvenile shrimps developed testicular tissues in the peripheral part of gonads during the age of 16–31 months and produced spermatozoa between 34 and 36 months. After reaching sexual maturity, male shrimps exhibited seasonal testicular development: active production of spermatozoa (February–May), disappearance of spermatozoa (spent, April–June), increase of spermatocytes (May–November), appearance of spermatids and spermatozoa in the gonads (November–February). The androgenic gland cells became larger and the rough endoplasmic reticulum in the cytoplasm developed at male sexual maturity. The cell structure shows that the androgenic gland hormone is a peptide. Furthermore, bilateral eyestalk ablation on immature male shrimps induced hypertrophy of the androgenic gland and acceleration of male sexual maturation. These results indicate the involvement of androgenic gland hormone and some eyestalk factor in regulating male sexual maturation. Over a 1-year laboratory-rearing period, some male shrimps (16.7%) changed sex. In transitional shrimps, testicular tissues in the gonads and androgenic glands degenerated; on the other hand, oocytes started yolk protein accumulation and hemolymph vitellogenin levels became high. These results suggest that androgenic gland degeneration is a trigger for sex change and that the vitellogenin level is a useful marker for sex change.

A population of humpback shrimp inhabiting Drury Inlet, British Columbia, was surveyed in November 2001 and March 2002 with trawl and trap fishing gear. Trawl catches were more representative of the shrimp population than trap catches in terms of age-structure and sex-stage proportions. Shrimp, as much as 81.4 tons, lived on a variety of benthic habitats, including deeper trawlable muddy and shallower untrawlable rocky areas. The shrimp population was comprised mainly of small age 1 shrimp (58% to 66%); the proportion that would be targeted by commercial fishers (i.e., larger older shrimp) was small (3% to 8%). Individual shrimp in the Drury Inlet population were generally smaller than shrimp reported from other areas of the BC coast. Females had not released their eggs in mid November and most (75%) were egg-bearing in mid March. Many more shrimp were in the transitional stage in March (24.9%) compared with November (0.4%). Shrimp numbers declined in trap catches at depths greater than 60 m. In ...

We determined the absolute (AIF) and relative (RIF) individual fecundity in a commercially important object, the grass shrimp, Pandalus kessleri (Decapoda: Pandalidae) near the Southern Kuril Islands. In the shrimps from Izmeny Bay (Kunashir Island) and the coastal area of the Southern Kuril Islands, the AIF equaled 192–918 (averaging 505) and 162–784 (459), respectively. In larger females, the AIF increases, reaches the maximum value, and then decreases again in the largest females. In June the AIF is smaller than in September, and in larger prawns, this difference is more pronounced. The mean large (D) and small (d) diameters of eggs equaled 1972 (1665–2400) and 1538 (1347–1900) μm, respectively; the D/d ratio equaled 1.28. The mean wet weight of an egg (w) was 3.43 mg (1.986–4.9) mg. From September 1 to November 30 D and d increased from 1894 to 2088 μm and from 1490 to 1567 μm, respectively. The factors affecting the fecundity of grass shrimp in Izmeny Bay are discussed.

Diet investigations were carried out on 0-, 1- and 2-year-old Northeast Arctic cod (Gadus morhua) sampled in the Barents Sea during 1984–2002. Stomach-content analyses showed that the 0 and 1 group cod fed mainly on crustaceans, with krill and amphipods composing up to 70% of their diet. Krill (Thysanoessa spp. and Meganyctiphanes norvegica) and amphipods (Themisto spp.) were mainly found in cod stomachs sampled in the central and close to the Polar Front region in the Barents Sea where these prey organisms are reported to be abundant in summer. A shift in the main diet from crustaceans to fish was observed from age 1 to age 2. The diet of 2-year-old cod mainly comprised capelin (Mallotus villosus) and other fish, and to a lesser degree, krill and amphipods. Shrimp (mainly Pandalus spp.) was also an important prey in both age 1 and 2 cod. A statistically significant positive relationship was obtained between capelin stock size and the amount of capelin in the diet of 2-year-old cod. Results from this study also show that the larger age-2 cod preyed more on capelin in winter and that larger cod (>22 cm) prefer larger capelin (>12 cm). During periods of low capelin abundance, the 2-year-old cod shift their diet more to crustaceans, such as krill and amphipods. A positive significant relationship was also obtained between Total Fullness Index (TFI) and the amount of capelin in the diet and between TFI and the growth of 2-year-old cod, indicating that the growth of age-2 cod is to a large extent dependent on the amount of capelin consumed. Growth of age-1 cod was also positively correlated to TFI.

Lipid class and fatty acid compositions were determined in shrimp larvae (Pandalus borealis and P. montagui) collected along transects across banks on the West Greenland shelf in June 1999, May and July 2000. The lipid class contents were investigated as indices of larval shrimp lipid condition and food type. Fatty acid compositions were investigated for lipid biomarkers to establish trophic relationships between larval shrimp and potential prey. Phospholipids were the dominant lipid class in all six pelagic development stages of larval P. borealis and P. montagui, accounting for 80 to 92% of the total lipid. In all six stages the contents of free fatty acids were more abundant than triacylglycerol. With increasing larval size from hatching to a carapace length of ~2.3 mm, there was a decreasing trend in the contents of hydrocarbons attributed to reduced amount of phytoplankton in the diet. Triacylglycerol (TG) content to wet weight ratio was investigated as index of nutritional larval condition and survival potential. Proportions of larvae with TG indices >0.2 were relatively high in May 2000 and June 1999, but generally low in July 2000. The fatty acids 16:0, 16:1n-7, 18:0, 18:1n-9, 18:1n-7, 20:5n-3, and 22:6n-3 were major lipid components of the larvae and their mean proportions varied within relatively small ranges between larval stages. The dominant fatty acids were 16:0, 20:5n-3, and 22:6n-3 with average proportions of about 17%, 20%, and 13%, as percentage of total fatty acids. Biomarkers for algae (16:0, 16:1n7, 18:1n-7, 20:5n-3, diatoms: elevated 16:1n-7/16:0 ratios), flagellates (18:0, 18:4n-3, 22:6n-3), and zooplankton (18:1n-9, 20:1n-9, 22:1n-11) indicate that larval P. borealis and P. montagui are omnivorous. ZI larvae in high concentrations at coastal and fjord stations in May 2000 and most larvae (ZIV–ZVI) from July 2000 were low in lipid. Larvae from June 1999 had relatively high lipid contents probably due to better feeding and growth history. Our results suggest variability in growth and survival expectations of larvae related to variations in larval food availability between years.

A eukaryotic parasite of uncertain taxonomic affiliation, with superficial similarity to parasitic dinoflagellates (large plasmodia and numerous trophonts) but a different mechanism of nuclear division and a lack of organelles characteristic of parasitic dinoflagellates, is described from spot prawns (Pandalus platyceros). Up to 20% of the spot prawns examined from Malaspina Strait, British Columbia, were infected. Infections in the majority of the prawns were cryptic (asymptomatic) but of sufficient duration to affect secondary sexual characteristics and castrate the host. Cryptic infections consisted of plasmodia containing numerous nuclei. The plasmodia were observed in the haemal sinuses of all tissues. In mature plasmodia the nuclei stopped dividing and showed a peripheral chromatin ring, an internal chromatin web, and up to three tiny nucleoli. Mature plasmodia divided into numerous uninucleate trophonts, resulting in symptoms of lethargy, orange discoloration, and milky haemolymph caused by a plethora of either spherical or discoid trophonts. Symptomatic infections of the prawns fished with traps rarely exceeded 2%. In 3 of the 156 symptomatic prawns examined, about 30% of the trophonts were in the process of binary fission. During mitosis the nuclear membrane was persistent, but openings (about 0.8 µm in width) at either pole accommodated emergent spindle-pole bodies to which the few chromosomes were attached by microtubules. Attempts to transmit the infection between prawns in the laboratory were unsuccessful.

There is strong evidence in the literature that energy supply for deep-sea scavengers is largely restricted to food falls of dead vertebrates such as fish and mammals. The problem for any scavenger inhabiting the seafloor is the unpredictability both in space and time of food fall events. It is generally accepted that chemoreception is one of the major means by which marine organisms detect food sources. Another major source of potential information, however, may come from hydroacoustic stimuli, which have long-range penetration. Such hydroacoustic stimuli will either arise when a large carcass hits and impacts the seafloor or during food consumption of scavengers producing feeding noises. The intensity and transmission characteristics depend upon sediment properties, size, weight and composition of the carcass as well as on size and mouthpart morphology of feeding individuals. In this study the relevance of hydroacoustic stimuli for food fall detection has been investigated in the pandalid shrimp Pandalus borealis Kroyer, 1838. The sensitivity of P. borealis to particle displacement amplitude was found to be close to values measured in other crustaceans. Based on 228 single experiments carried out with five specimens, our results indicate that low-frequency noises may be helpful in detecting food fall events but only in the near-field. In this paper we suggest that the impact of a sinking carcass at the seafloor is a likely source producing elastic waves at the water–seafloor interface. Based on both empirical findings and general theoretical calculations of elastic waves originating from a sinking object hitting the seafloor we conclude that such “micro seismic events” may allow resting scavengers even several hundred metres away to detect a food source.

Sex change, growth, and mortality of Pandalus populations are important to stock management. To investigate the importance of these life history traits in setting management strategies, we performed a variety of simulatoins using a length-based model. We compared three populations: a Kachemak Bay, Alaska type (K_pop); a hypothetical one with the same growth but without sex change (H_pop); and a northern Barents Sea type (B_pop). The main difference between K_pop and B_pop is growth rate; K_pop has faster growth and a shorter live span, whereas B_pop lives farther north, and therefore has slower growth and greater longevity. We found that populations with sex change were more sensitive to fishing pressure. Continuous fishing was detrimental to K_pop when instantaneous fishing mortality was above 0.3, but threshold management, i.e. closing the fishery at a low population level, greatly improved the population performance. B_pop, the slower-growing, longer-lived population required larger mesh sizes than K_pop, but increasing mesh size could not prevent collapse under high fishing mortality, and fishery closure under threshold management was necessary to sustain the population. Abrupt decrease of age one and two males caused populations with sex change to fluctuate in spawning biomass. Seasonality in growth and natural mortality is also pertinent to shrimp management. Given faster growth in summer, higher natural mortality in summer means fishing after spring hatching tends to result in higher cumulative yield than fishing after fall mating, and vice versa. In addition, fishing after hatching is in general more robust to overfishing. From the simulation analyses, we concluded that both sex change and seasonality of growth and mortality of Pandalus populations should be taken into account in shrimp management.

Eye lipids and their fatty acid composition were analysed in the Japanese Procambarus clarkii and the Finnish Astacus fluviatilis, two taxonomically related species of crayfish occurring in similar habitats, but separated geographically by 25° of latitude. Of the total lipids in the P. clarkii eye 43% were phosphatidylcholine-lipids (PC) and 19% were phosphatidylethanolamine-lipids (PE), whereas these phospholipids in A. fluviatilis were 18% and 52%, respectively. In the cooler waters of Finland, Astacus may have difficulties converting PE-lipids to PC-lipids, a problem that P. clarkii may not have in the warmer Japan. In this respect, eye lipids from Artemia reared at 27°C resemble those of P. clarkii, while Astacus eye lipids are similar to those of the cold deepwater prawn Pandalus [4]. The analysis of the fatty acids suggests that A. fluviatilis at 17°C had a greater need to stabilize its membranes than P. clarkii at 25°C.

Food items and metazoan parasites were identified from the stomachs of 80 yearlings and 150 two-year-old saithe (Pollachius virens (L.)), sampled from the coastal waters of the Faroe Islands. Of a total of 65 food items found, 47 were identified to species or genus. Yearlings fed mainly on Parathemisto spp., euphausiids, Pandalus sp. and Aphrodita aculeata, while the two-year-old saithe exploited mainly euphausiids (especially Meganyctiphanes norvegica), sandeels (Ammodytes spp.) and gastropods (especially Littorina spp.) Parasites found included the nematodes Anisakis simplex, Contracaecum sp., Hysterothylacium aduncum and Cucullanus cirratus; the copepod crustaceans Caligus sp. and Clavella sp.; the acanthocephalan Echinorhynchus gadi; a single digenean trematode; and a single cestode plerocercoid. Adult saithe from the Faroe Shelf preyed mainly on fish (Trisopterus esmarki, Microesistius poutassou and Melanogrammus aglefinus), and saithe from Faroe Bank on M. norvegica. A discussion on a possible trans...