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Bryozoan epibiosis on lobster hosts is rarely reported. Here we document bryozoan fouling of the spiny rock lobster Jasus edwardsii from the Hauraki Gulf, North Island of New Zealand. The 92 lobste...

Polymorphic microsatellite loci were isolated for Panulirus ornatus using 454 GS-FLX Titanium pyrosequencing. Fifteen markers containing perfect di-, tri-, tetra-, and penta-nucleotide motifs were consistently co-amplified in five multiplexes in a panel of 91 randomly selected samples. Observed number of alleles varied from 2 to 14 per locus. Observed and expected heterozygosity ranged from 0.090 to 0.79 and 0.08 to 0.87, respectively. Ten loci deviated from Hardy-Weinberg equilibrium after sequential Bonferroni correction. Genetic linkage disequilibrium analysis between all pairs of the loci showed significant departure from the null hypothesis between 11 loci. The microsatellite markers were also amplified successfully in related Panulirus homarus species with adequate level of polymorphism. The successful cross-species primer amplification of the 15 microsatellites indicates the potential of the developed markers to be transferred to other Panulirus species. The 15 novel microsatellite markers reported in this work add to the previously characterized markers by our group, exhibit adequate levels of polymorphism for wide range of future studies investigating population structure, genetic diversity, and evolutionary relationships among Panulirus species.

Lobsters constitute low-volume high-value crustacean fishery resource along Indian coast. For the conservation and management of this declining resource, accurate identification of species and larvae is essential. The objectives of this work were to generate species-specific molecular signatures of 11 commercially important species of lobsters of families Palinuridae and Scyllaridae and to reconstruct a phylogeny to clarify the evolutionary relationships among genera and species included in this study. Partial sequences were generated for all the candidate species from sampling sites along the Indian coast using markers like Cytochrome oxidase I (COI), 16SrRNA, 12SrRNA, and 18SrRNA genes, and analyzed. The genetic identities of widely distributed Thenus species along the Indian coast to be Thenus unimaculatus and the sub-species of Panulirus homarus to be P. homarus homarus were confirmed. Phylogeny reconstruction using the individual gene and concatenated mtDNA data set were carried out. The overall results suggested independent monophyly of Scyllaridae and Stridentes of Palinuridae. The interspecific divergence was found to be highest for the 12SrRNA compared with other genes. Significant incongruence between mtDNA and nuclear 18SrRNA gene tree topologies was observed. The results hinted an earlier origin for Palinuridae compared with Scyllaridae. The DNA sequence data generated from this study will aid in the correct identification of lobster larvae and will find application in research related to larval transport and distribution.

The morphometric relationship of carapace length (CL) to tail width (TW) of southern rock lobster (Jasus edwardsii) was determined to assist enforcement of existing minimum size limits and also to enable the development of an upper size limit in Tasmania. Data were collected from southern rock lobsters in the wild and at processors and used to develop a system for measuring TW which reduces measurement error. Linear regression was used to define the relationship between CL and TW for males (TW = 0.4107x+14.058, R2=.9236, n=1003) and females (TW=0.5756x+2.2884, R2=.9323, n=503). Logistic regressions provide the TWs associated with the probability (0.5, 50 and 95%) of a lobster having a carapace equal to or more than the theoretical size limits. Regional differences in the morphometric relationship were evident but would not prevent the use of size limit based on TW if a conservative probability value were used.

The ability of Panulirus ornatus phyllosoma to capture, feed and process diets of different texture and particle size were studied during developmental stages I, III and V. Diets were captured using the spines and dactyl on the second and third pereiopods and brought to the oral cavity assisted by the second and third maxillapeds. Optimal capture was obtained when diets were a gelatinous-muscular consistency, and hard particles were caught when embedded in a muscular carrier. A range of food textures, from gelatinous to hard, were able to be masticated in the oral cavity by stage V phyllosoma. Masticated particles were filtered by phyllosoma through spines and hairs in the proventriculum, during stages I–II, and a filter press in stages III–V. Maximum particle size passing into the midgut gland for digestion was 7, 3 and 0.5 µm in stage I, III and V phyllosoma, respectively. B cells were prominent in the proximal ends of the caece of stage V phyllosoma and were visible in live animals under light microscopy.

The eastern rock (spiny) lobster, Jasus verreauxi occurs along the east coast of Australia and North Island of New Zealand. The resource off New South Wales (NSW), Australia, is managed through a suite of input controls and individual catch quotas. The stock assessment process has identified that the length‐based model used in annual stock assessments would be improved with more precise information about the species’ growth patterns. This study provides the first published information on a growth model for this species by describing the results of tagging experiments from 1995 to 2001 (inclusive). Lobsters were tagged with anchor tags across six locations spanning the main distribution of the species off NSW. The maximum time that a tagged lobster was at liberty was 2573 days. Recapture data were fitted to the von Bertalanffy growth function (VBGF) using Fabens method, including parameters for seasonal growth and individual variability in growth, and extraneous information about the average lengt...

We histologically determined lipofuscin content in eyestalk neural tissue to estimate the age and growth of Caribbean spiny lobster (Panulirus argus) in Florida, United States. Neurolipofuscin was measured from size‐stratified samples of 145 lobsters from the Florida Keys and 119 lobsters from the Dry Tortugas, the two main fishing areas in Florida. Modal analysis of the neurolipofuscin concentration frequency histograms suggested a relatively constant neurolipofuscin accumulation rate of 0.27% by volume (%VF) per year, which corresponded with the annual accumulation rate of 0.29%VF previously measured in the laboratory. Verification of the similarity of neurolipofuscin accumulation rates for lobsters in the field with previous laboratory studies indicates that neurolipofuscin concentration is suitable for estimating population parameters for P. argus. Neurolipofuscin‐based age estimates of lobster populations from the Florida Keys and Dry Tortugas, developed from Monte Carlo simulations of size‐...

The effect of feeding frequency and ration level on the growth and survival of early (5–10 mm CL) juvenile spiny lobster, Panulirus argus, was determined. Animals were either fed 100% body weight (BW)/day in the evening, coinciding with the change from light to dark, or 50% BW/day twice (once in the morning and once in the evening) daily, also coinciding with light transition. Feeding to excess once daily resulted in significantly (P> 0.05) greater weight and carapace length (CL) increases during the 28-day experiment, compared with the same overall ration divided between two feeding times. Survival rates between treatments were not significantly (P> 0.05) different during the trial. The implications for early juvenile spiny lobster culture are that feeding a high-ration once daily, at the onset of dusk, as compared with feeding half of the daily ration twice daily, results in improved growth rates.

A comparison of the documented ecology and behaviour of the separate phases in the life cycles is presented. Data gathered during the review show that during the evolution of the family from deeper-water habitats to the more rapidly fluctuating shallower waters, there have been many biological adjustments at each phase in their life cycles. In the more ancient Stridentes genera, like Puerulus, the larvae are found well below the surface waters and the pueruli often settle at greater depths than those of the adults. Long incubation times, few larval instars, and year-round spawning are probably their life cycle characteristics. As an "intermediate-evolved" genus of Stridentes, Palinurus lives along the outer shelf, grows slowly, matures late, and breeds seasonally once a year. Incubation time is long, the larvae live at depth, the number of larval instars is limited, and the puerulus is a weak swimmer. Settlement is often downstream of the breeding stock. Incubation times are short for the more recently evolved Stridentes Panulirus, the larvae pass through many instars in the surface waters to c. 200 m. Some pueruli settle in special coastal habitats, others settle in the same habitat as the adult. Breeding in the cooler water First Major Lineage species is seasonal, one or two broods being produced. Most of the species in the tropical Second Major Lineage are faster growing, breed repetitively over a long breeding season, and have a shorter larval life. For the Silentes, the trend in biological changes from deep to shallower water is comparable with that of Stridentes. Incubation is probably long in the more ancient Projasus, the larvae are rare in surface waters and the pueruli settle at depths similar to those of the adults. Sagmariasus and Jasus breed once during a defined season, incubation time is moderate, and the larvae pass through many instars. The pueruli of Sagmariasus settle downstream and exhibit contranatant migration whereas the pueruli of Jasus swim strongly to their shallow habitats. In each life cycle phase, migration methods range from vertical paddling in phyllosomata, horizontal swimming in pueruli, and horizontal walking when juveniles move to adult habitats. Adult movements are associated with foraging, searching for shelter, avoiding adverse seasonal conditions, or walking to preferred offshore locations for moulting and reproduction.

The larvae or phyllosomes of many species of spiny lobsters (Palinuridae) are known to complete their development in offshore oceanic waters. Phyllosomes metamorphose to non‐feeding, nektonic post‐larvae or pueruli, which move into shallow coastal waters where they settle to become benthic dwelling juveniles. There is growing evidence that the movement of pueruli is directed toward the coast rather than a process of random dispersal. The migration inshore by the non‐feeding pueruli is likely to be one of the more extreme examples of onshore orientation among marine organisms, but is still poorly understood. This article provides a synthesis of the current state of knowledge of the possible cues and sensory mechanisms that might be used by pueruli of spiny lobsters for orienting toward the coast from offshore waters. The review is used to identify the potential cues that would benefit from future research efforts.

Any attempt to enhance rock lobster production by increasing survival after settlement, or by ongrowing or outplanting young juveniles, requires knowledge of the shelter preferences of young juveniles. For juvenile Jasus edwardsii in the wild these are not well known. Information available suggests that juveniles up to c. 35 mm carapace length (CL) occupy shelters that generally conform closely to their body dimensions but that larger juveniles use shelters of more variable dimension, often much larger than their body size. We investigated mainly physical factors important in shelter choice by 15–59 mm CL (c. 2–24‐month‐old juveniles) in laboratory tank experiments. In overnight tests, all sizes of juvenile lobster chose to occupy holes (shelters with sides) over open horizontal gaps. Preference for open horizontal gaps versus horizontal crevices (where the height reduces from a maximum at the mouth to zero at the opposite end) was much less clear‐cut; choice varied according to lobster size. For...

We studied the properties of currents generated in Xenopus oocytes by nine splice variants of the spiny lobster Shaker gene. These isoforms differ in their amino termini and in the P-loop region of the pore. Both the voltage dependence and kinetic properties of the currents varied significantly, depending on which amino terminus was present. A cluster of net positive charges at the N-terminus was not necessary for rapid inactivation: negatively charged N-termini also inactivated rapidly. There was no obvious correlation between N-terminus length and inactivation rate. These N-terminal effects were additive with a separate set of voltage and kinetic properties controlled by the two alternative P-loop exons.

Concern for the sustainability of spiny lobster (Decapoda: Palinuridae) fisheries has created significant interest in their aquaculture. However, attempts to culture spiny lobsters from eggs to pue...

The maintenance of long‐term associations with particular reef sites is likely to have contributed to the rebuilding of the spiny lobster population (Jasus edwardsii (Hutton) (Decapoda: Palinuridae)) in the Leigh Marine Reserve, in northeast New Zealand. Between 1983 and 1985, 429 lobsters were tagged underwater with western rock lobster tags and antennae tags. Underwater tagging and commercial traps were used to tag a further 737 lobsters with T‐bar tags and antennae tags between 1994 and 1996. Twenty‐one percent of lobsters resighted (n = 323) between 1983 and 1985 maintained their association with a 15 ha reef inside the reserve for 1–8 years. Site association tended to increase with female size, whereas site association in males was relatively constant until 130 mm carapace length, and then markedly increased. Legal‐sized lobster abundance fluctuated seasonally, suggesting that a proportion of the population undertook larger‐scale movements beyond the reef. This was confirmed during a second ...

Summary The present study describes the formation and fine structure of the different appendages during embryogenesis in the spiny lobster Jasus frontalis, as viewed with scanning electron microscopy (SEM). Fresh materials for study were obtained under laboratory conditions, with developing embryos maintained at 17±1.5°C. Seven different stages were defined from spawning to hatching, lasting 69–91 days. The oval shape of the embryos range in major diameter from 602±21.2.μ at the first stage and 717±30.5μ at the seventh stage, increasing the total volume by 66.8%. The results showed numerous similarities to data obtained for other crustacean species, plus several previously unreported features particular to this lobster. The most conspicuous difference with other decapods is the high degree of development of the antennae II and the slight development of the rudimentary abdomen.

We describe from surface waters near Tonga a subfinal or final stage phyllosoma larva with a circular cepahalon which we refer to Puerulus angulatus (Bate, 1888). It is the largest and most advanced larva of Puerulus yet described, and is only the second larva from the South Pacific Ocean for this genus.

Material previously identified as Panulirus longipes femoristriga (von Martens, 1872) is found to have two forms of coloration, namely the banded whisker form and the white whisker form. Careful comparisons of fresh lobsters reveal that the two forms differ in morphological characters. Data from allozyme analysis also shows that they are genetically distinct. To stabilize the confused taxonomy of these species, a neotype for P. longipes femoristriga is selected from a specimen of the banded whisker form from the type-locality Amboina. The white whisker form is shown to be a new species.

A new species of rock lobster, Jasus caveorum, is described from commercial catches taken on a non‐emergent seamount in the eastern South Pacific Ocean. The species best fits the "frontalis subgroup” of the "lalandii group” of Jasus lobsters. J. caveorum is most similar to J. frontalis from the eastern South Pacific, but differs clearly from that species in having very little abdominal “squamous” sculpturing.

A total of 3417 rock lobsters (Jasus edwardsii) were tagged and released during five separate tagging periods between February 1979 and September 1982, along the Fiordland coast between Thompson and Caswell Sound, New Zealand. Up to 31 May 1987, 1580 individual rock lobsters (46% of those tagged) had been returned, with 1470 having information on the location of recapture. 145 (10%) of the latter had moved at least 5 km from the tagging site. The longest minimum straight‐line sea distance moved by any one animal was 161 km. The largest proportions of rock lobsters that moved and those that moved the longest distances were immature females and small males. The movements of these two sex/maturity stages showed a definite directionality, with most recaptures moving north. Smaller proportions of mature females moved, and they showed no directionality. The multiple recaptures of some mature females during and immediately after the egg‐bearing season suggested that homing of some animals may have occurred.

The palinurid rock lobster, Jasus verreauxi, has a disjunct distribution, occurring on the east coast of Australia and in New Zealand. Oceanic currents flowing across the Tasman Sea from Australia towards New Zealand and the long life of phyllosoma larvae suggests larval mixing and, consequently, genetic similarity between these populations. However, restriction endonuclease analysis of the mitochondrial DNA (mtDNA) of 25 late juvenile and adult lobsters showed that Australian and New Zealand haplotype assemblages are defined by two restriction sites, one confined to each locality. Genetic differentiation between Australian and New Zealand J. verreauxi was also supported by gene diversity analysis (GST). In contrast to the results from a similar study of a congeneric species with an analogous distribution (J. edwardsii), these preliminary results suggest that larval exchange between adult populations across the Tasman Sea may be limited.

Settlement of the puerulus stage of Jasus edwardsii (Decapoda: Palinuridae) near the shore takes place over a wide depth range. It occurs intertidally, and, as determined by crevice collectors, als...

Settlement of puerulus‐stage New Zealand red rock lobsters (Jasus edwardsii) and abundance of the first three juvenile cohorts were measured from 1981 to 1989 near Halfmoon Bay, Stewart Island. Puerulus settlement on subtidal collectors shows great annual variation. Juvenile abundance, estimated from the number caught in annual diver collections, shows less variation. One‐year‐olds appear less vulnerable to diver sampling than older juveniles. Abundance of 2‐ and 3‐year‐olds is highly correlated with puerulus settlement 2 and 3 years previously. Survival between puerulus and 1+ stages appears to be density‐dependent, but survival of older juveniles does not. Size is inversely related to abundance in 3+ females but not in the other cohorts, suggesting density‐dependent growth between ages 2 and 3. Puerulus settlement rates and processes on shallow inshore reefs appear to be important in determining recruitment strength in this species.

One hundred and nineteen of the 1246 Jasus verreauxi tagged at 5 locations along the eastern coast of the North Island, New Zealand, during 1978–82 were recaptured by 31 May 1983. Seventy two of the recaptures were local (< 15 km from tagging site). All long distance movements (≥15 km) were in a general north‐westerly direction towards the main breeding ground off Cape Reinga, with an overall average minimum distance moved of 142.3 km, at an average rate of 0.61 km d‐1. The movement towards Cape Reinga is probably critical in the recruitment mechanism for this species.

The smallest size at which at least 50% of female Jasus verreauxi bore eggs during the egg‐bearing season (= size at onset of breeding) was ≥ 160 mm carapace length (CL) (range 160–184 mm CL). This was usually at least 10 mm CL greater than the size at which setae first developed on the endopodites of the pleopods, and amounts to at least a 2‐year age difference. An increase in the minimum legal size to at least 160 mm CL is necessary if it is considered desirable that most females be allowed to breed before becoming available to the fishery.

The complete series of phyllosoma larval stages of spiny lobster lasus edwardsii are described. Eleven stages are recognised from specimens captured in plankton samples collected along a transect extending 185 km east of Castlepoint, North Island, New Zealand between July 1969 and December 1971. A table of distinguishing characteristics and a key for identification of stages are presented. First stage larvae occur between August and October and last stage larvae about 15 months later. Mortality through the phyllosoma stages is estimated to be 98%. Early stage larvae occur mainly inshore in Southland Current water in the upper 5 m, and later stage larvae occur more frequently offshore in East Cape Current water at 40–60 m depth.

Annual growth, growth per moult, moult frequency, and moulting seasons were estimated for rock lobsters Jasus edwardsii tagged in three areas around Stewart Island. There were no significant differences in growth parameters between the areas within the size range 70–99 mm carapace length, although differences between Stewart Island and previously reported data from Gisborne were noted. There were significant differences in growth between the sexes. Females reached minimum legal size at about 6 years and sexual maturity at about 8 years after settlement. Males reached minimum legal size at just under 6 years.

Numbers of the puerulus stage of the rock lobster Jasus edwardsii (Hutton) in the inter‐tidal zone at Kaikoura, New Zealand (42° 25’ S, 173° 42’ E) appear to have been much greater during 1967–72 than during 1984–87. The catch of pueruli on nearby subtidal collectors has been low since at least 1980 compared with some other parts of the country. The reduction in puerulus numbers at Kaikoura may result from fewer phyllosoma larvae offshore. A consequence of this is a possible decline in rock lobster catches in the Kaikoura fishery.

Dense aggregations of large ovigerous female rock lobsters, Jasus edwardsii, observed by divers at several places around central New Zealand, are described. Such aggregations are typically seen in late winter in areas of strong tidal water movements, and in the absence of suitable shelter they take the form of defensive circles and heaps. We suggest that this behaviour may facilitate rapid dispersal of newly hatched larvae.

The occurrence of the puerulus and post‐puerulus stages of the palinurid rock lobster Jasus edwardsii (Hutton) on the shore and on moored collectors at Castlepoint (40°54/S, 176°14'E) was monitored during 1974–77. Various types of collectors were tested; the least expensive and most robust, which also had the highest catches of larvae, incorporated a series of marine grade plywood sheets held in a metal frame and spaced to give a gap size of 10—15 mm. Large catches (in excess of 10) were made only after the collectors had been immersed in sea water for several weeks. The main period of settlement was December to July, with peaks in January‐February and April‐June. Although no clear correlation between settlement and wind direction was evident, the best correlation was found with onshore winds from the directions 120°‐200°. Only one moult was observed between the recently settled puerulus larva and the fully pigmented, post‐puerulus rock lobster, probably occurring 2–3 weeks after settlement. Pigmentation ...

More than 4000 specimens of the puerulus stage of the rock lobster, Jasus edwardsii, were collected in the sea water intake of the New Plymouth Power Station during 1977–84. Most specimens were caught between July and September. Sizes of pueruli were similar within years, but there were significant differences in size and number of pueruli between years. Puerulus occurrence was correlated with the late winter and spring increase in frequency of onshore winds, but the seasonality in settlement was probably not caused by this factor alone. Most pueruli at the power station were 9–13 months old, and occurred at any part of the lunar cycle. Oceanic flow patterns in the region suggested that most specimens originated from hatchings along the west coast of New Zealand, north of Hokitika. As the high numbers of pueruli at the power station were inconsistent with the zero catch of pueruli on adjacent collectors, and with the relatively low numbers of juveniles and adults nearby, the power station may att...

A total of 4393 female and small male rock lobsters, Jasus edwardsii, were tagged and released near Stewart Island and in eastern Foveaux Strait between 1974 and 1978. Most recaptures had not moved more than 5 km but 16% of immature females and small males underwent highly directional movements along the southeast coast of Stewart Island, and 16 were recaptured in Fiordland. Rock lobsters which undertook long distance movements included those which were classified by fishermen as migratory animals, plus some small, local inshore animals. These observations add support to the hypothesis that a regular migration of immature rock lobsters takes place around southern New Zealand, probably with no single area of origin or destination.

Mating and egg laying behaviour of specimens of rock lobster, Jasus edwardsii (Hutton), were observed in aquaria. Mating occurred within 6 weeks of a female moult and egg laying took place within a few hours of mating. The pattern of precopulatory behaviour, mating, and egg laying has many similar features to that reported for Panulirus homarus. Accounts of mating and egg laying in J. lalandii are conflicting, some showing similarities with J. edwardsii and others, major differences.

The size at the onset of sexual maturity for female rock lobsters, Jasus edwardsii, was defined as the size or size class at which 50% of the rock lobsters in a sample were mature, and was estimated at 27 localities around New Zealand. Animals were regarded as mature if they were bearing external eggs attached to the pleopods or if there were well developed setae on the endopodites of the pleopods. Samples from the same location in different years showed little variation in the size at the onset of maturity. There was, however, considerable variation between localities, ranging from 72 mm carapace length near Gisborne to 121 mm carapace length in eastern Foveaux Strait. Size at the onset of maturity showed an inverse relationship with water temperature. The relationship between the size at the onset of maturity, age, growth rate, and water temperature is discussed.

Summary Fecundity in the New Zealand spiny lobster Jasus edwardsii (Hutton) has been investigated by a detailed examination of 14 selected females “in berry” (i.e. carrying external eggs), ranging in carapace lengths from 9.5 cm to 17.0 cm. The following data were obtained for each specimen: (a) the total weight of eggs carried, (b) the average number of eggs per 1 g sample, and (c) the total number of eggs carried. A positive correlation was noted between the total weight of eggs carried and increase in carapace length. The total weight of eggs carried ranged from 26.9 g in a small specimen of 9.5 cm C.L., to 123.9 g in a large female of 16.0 cm C.L. No relation was found between the average number of eggs per 1 g sample and increase in carapace length. A low count of 3,541 eggs per 1 g sample was recorded, and a high count of 5,005 eggs. A direct relation was noted between the total number of eggs carried by J edwardsii and increase in carapace length. The number of eggs carried ranged from a low figure...

Post‐puerulus specimens of Jasus edwardsii (Hutton) have been successfully reared in the laboratory from the puerulus stage for periods of up to 12 months. The spiny lobsters were reared in concret...

Summary Two species of spiny lobsters (marine crayfish) inhabit New Zealand waters: Jasus edwardsii (Hutton, 1875), and J verreauxi (H. Milne Edwards, 1851). J edwardsii, the more common species, is present along most rocky coastlines in New Zealand, but is more abundant in the south‐west of the South Island and at the Chatham Islands. The species apparently reaches its northern limit of distribution at the Three Kings Islands (34°S) and its southern limit at the Auckland Islands (51°S). J. verreauxi, the less common species, is almost solely restricted in New Zealand waters to the north‐east coast of the North Island. It is uncommon in the west and the south of the North Island, and is rare in the South Island. J. verreauxi apparently reaches its northern limit of distribution at the Kermadec Islands (31°S), and its southern limit near Bluff (47°S) in the South Island.

Summary All species of Jasus inhabit continental or island waters of the Southern Ocean. The are six species in the J. lalandii group which contains all but one of the known species of Jasus. Within the J. lalandii group two subgroups, each comprising three species, are recognised. Taxonomic variation is discussed and a key for identification presented. For efficient management, administrators should know the geographic limits of species on which fisheries are based.

Summary Jasus verreauxi (H. Milne Edwards)—known locally as the packhorse crayfish— is the less common of the two New Zealand species of spiny lobster (marine crayfish; J. edwardsii is the other), and is commercially important only in the north‐easlt of North Island. About 80% of the annual J. verreauxi catch is landed in 5 months of the year: November, December, January, February, and March. The fishery is small and unimportant compared with the total New Zealand fishery for both spiny lobster species. During the 5 years of this study (January 1962‐December 1966) the commercial catch of J. verreauxi amounted to only about 0.7% of the total spiny lobster catch during the same period. Limited daita collected by Marine Department suggest that the J. verreauxi fishery showed a downward trend during this period. J. verreauxi and J. edwardsii fisheries are briefly compared and biological differences between the two species are discussed.

Summary Fecundity in Jasus verreauxi (H. Milne Edwards, 1851) has been studied by a detailed investigation of (a) the total weight of eggs carried by female specimens, (b) the average number of eggs per 1 g sample, and (c) the total number of eggs carried by females. In mid October 1966, 217 females “in berry” (that is, carrying external eggs) were examined and measured at Spirits Bay, New Zealand. The fecundity study is based on the results obtained from 21 selected specimens, with carapace lengths from 15.5 cm to 23.5 cm. A direct relation was found between the total weight of eggs carried and increase in carapace length. The total weight of eggs carried varied from about 51 g to 238 g for carapace lengths of 15.5 cm to 23.5 cm. No correlation was shown between the average number of eggs per 1 g sample and increase in carapace length. Considerable variation was noted in the number of eggs per 1 g sample, which ranged from a low count of 6,453 eggs to a high count of 8,341 eggs. The total number of eggs ...

Summary The carapace length and total length size at first maturity in females of Jasus verreauxi (H. Milne Edwards, 1851) has been investigated by a detailed study of (a) the detection of the smallest size class with external eggs, and (b) the incidence of egg‐carrying females per size‐class interval. For the study 834 females were measured and examined at Spirits Bay, New Zealand, during mid October and late December 1966. The specimens ranged in carapace length from 12.0 cm to 23.9 cm, and in total length from 29.0 cm to 56.9 cm. The results of the study show clearly that the females reach first maturity at a carapace length or a total length larger than the present minimum legal size, i.e. a carapace length of 10.2 cm (4.02 in.), or a total length of 25.4 cm (10.0 in.). No mature females were found less than 13.5 cm carapace length, or 32.0 cm total length. First maturity was attained by the majority (50% or more) of the J verreauxi females at a carapace length of 15.3 cm or larger, or at a total leng...

Summary The spiny lobster Jasus edwardsii (Hutton) supports a thriving new fishery at the Chatham Islands, about 770 km east of New Zealand. Commercial fishing for J. edwardsii started in November 1965, and within 2 years the area became a major centre of New Zealand's large spiny lobster fishery, which earned >NZ$5,000,000 in 1967. Over 12 months (September 1966 to August 1967) landings at the Chatham Islands made up 39.8% of the total New Zealand spiny lobster catch of 16,600,0001b. In the first year of fishing 2,177,923 lb of spiny lobsters were caught, and in the second 7,129,658lb—a 227% increase. Fishing effort also increased substantially: average number of boats fishing each month rose by 174% in the second year, and the total number of boat‐fishing days by 152%. Most specimens of J. edwardsii caught are large and mature, typical of a virgin stock.