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From 2011, lamprey (Geotria australis) populations in Southland, New Zealand have been affected by reddening along the length of the body and increased mortalities, termed lamprey reddening syndrome (LRS). Molecular testing, bacteriology, histopathology and epidemiology were used to determine if an infectious agent was present and to increase the understanding of this syndrome. An atypical Aeromonas salmonicida was detected from affected lamprey in 2011. This organism has not previously been reported from New Zealand. Investigative molecular testing indicated the organism was an uncharacterised, unculturable, atypical A. salmonicida and a likely incidental finding. Histopathology did not indicate an infectious process was involved, but suggested the reddening may be due to blunt trauma. Epidemiological investigation found the Mokoreta River had a significantly higher prevalence of LRS than others in the Southland region, but there was no clear reason why. To date, no infectious aetiology for this syndrome has been identified.

An investigation was conducted to identify the cause of mortalities in freshwater reared Chinook salmon (Oncorhynchus tshawytscha). Mortalities occurred in juvenile salmon, at a salmon rearing facility in the South Island of New Zealand. The affected fish were from a pen inside the facility with no surrounding pens or other year classes affected.Clinically affected fish presented with skin lesions. The majority of skin lesions were unruptured, boil-like, raised circular masses up to 4 cm in diameter, particularly on the dorsolateral aspects and the flank. A number of fish presented with large ulcers resulting from rupturing of the raised lesions described above. This clinical presentation showed similarities to that of furunculosis caused by typical Aeromonas salmonicida, a bacterium exotic to New Zealand.Samples were taken from two representative fish in the field for histopathology, bacterial culture and molecular testing. Histopathological findings included granulomatous lesions in the kidney, liver, spleen and muscle. When stained with Fite-Faraco modified acid fast stain filamentous branching rods were identified within these granulomas. Following bacterial culture of kidney swabs pure growth of small white matt adherent colonies was observed. This isolate was identified as a Nocardia species by biochemical testing and nucleotide sequencing of the partial 16S rRNA gene. All samples were negative for A. salmonicida based on bacterial culture and PCR testing.Nocardiosis caused by a Nocardia species.Nocardiosis in these fish was caused by a previously undescribed Nocardia species that differs from the species known to be pathogenic to fish: N. asteroides, N. salmonicida and N. seriole. This bacterium is likely to be a new or unnamed environmental species of Nocardia that has the potential to cause disease in Chinook salmon under certain conditions. The clinical presentation of this Nocardia species manifested as raised, boil-like skin lesions which has similarities to the presentation of furunculosis caused by the bacterium typical A. salmonicida, a species exotic to New Zealand.

In the summer months of 2015 Chinook salmon, Oncorhynchus tshawytscha (Walbaum), were submitted to the New Zealand Ministry for Primary Industries (MPI) for disease investigation. Gross examination of 10 moribund fish revealed multiple areas of ulceration over all areas of the body including fins and mouth in eight of the 10 fish. Pale livers (n = 4), mottled appearance of the kidney (n = 5) and reddening of the distal intestines (n = 5) were also observed. As these fish presented with skin lesions, Piscirickettsia salmonis was included as a differential diagnosis. Testing for this agent was conducted and a rickettsia-like organism (RLO) was detected by histopathology in seven fish and by molecular methods in three fish. Nucleic acid sequencing revealed that this organism had highest similarity to a piscirickettsia-like organism with a 19 base pair (bp) deletion in the internal transcribed spacer (ITS) region of the rDNA operon when compared to the reference strain P. salmonis, LF-89 (ATCC VR-1361...

In November 2013 the Animal Health Laboratory, Ministry for Primary Industries, New Zealand, received a report of a grey mullet (Mugil cephalus) presenting reddish-white granular lesions across its body. Gross pathological examination revealed cyst-like lesions on the distal portion of the scales and proximal part of the fins. Giemsa-stained wet preparations of these lesions presumptively identified spores as Myxobolus sp. DNA sequencing of the 18S rRNA gene further identified these spores as Myxobolus episquamalis. This is the first report of Myxobolus episquamalis infecting M. cephalus from New Zealand.

The degree to which the parasites and diseases of New Zealand fish and shellfish have been studied reflects the commercial importance of the host concerned and the severity of infection. As New Zealand aquaculture is largely based on farmed bivalve molluscs and salmonids, most attention has been given to these groups. However, by far the most serious parasitic disease of bivalves, Bonamia sp. in flat oysters (Tiostrea chilensis), is primarily a problem in wild fisheries. The importance of Bonamia sp. is such that this review will deal largely with bonamiasis but will also mention other parasites of New Zealand fish and shellfish. Crustaceans have received very little attention, because only rock lobsters (Jasus edwardsii) support a substantial fishery, and there are no known parasitic diseases of this species. Marine fishes have been poorly surveyed for parasites, but the presence of Anisakis spp. larvae and cestode plerocercae in fillets are of increasing public health concern.

The occurrence of trauma, consistent with healing net damage, was observed in 1988 from the New Zealand west coast hoki fishery, where hoki (Macruronus novaezelandiae), hake (Merluccius australis), silver warehou (Seriolella punctata), rays bream (Brama brama), and frostfish (Lepidopus caudatus) were affected. In 1989 and 1990 similar trauma was observed on hoki from the New Zealand Southern Plateau. Data on prevalence of cuts, scrapes, and scars are provided for the Southern Plateau. In some of the tows recorded from the Southern Plateau, over 5% of the fish caught had previous encounters with nets.

Fishers have been complaining about the effects of bottom trawl gear on the marine environment since at least the 14th century. Trawl gear affects the environment in both direct and indirect ways. Direct effects include scraping and ploughing of the substrate, sediment resuspension, destruction of benthos, and dumping of processing waste. Indirect effects include post‐fishing mortality and long‐term trawl‐induced changes to the benthos. There are few conclusive studies linking trawling to observed environmental changes since it is difficult to isolate the cause. However, permanent faunal changes brought about by trawling have been recorded. Research has established that the degree of environmental perturbation from bottom trawling activities is related to the weight of the gear on the seabed, the towing speed, the nature of the bottom sediments, and the strength of the tides and currents. The greater the frequency of gear impact on an area, the greater the likelihood of permanent change. In deepe...

Five new species of Hatschekia are described from the gills of teleost fishes. From a coral reef at Rangiroa, French Polynesia: Hatschekia napoleoni from Cheilinus undulatus; H. manea from Scarus gibbus; H. becuni from Sphyraena forsteri; and H. girelli from Thalassoma fuscum. From deeper water (200–300m) around the New Zealand coast: H. squamata from Paratrachicthys trailli.

A new species of cyclopoid copepod belonging to the genus Lichomolgus Thorell, 1859, obtained from the gills of the bivalve Perna canaliculus (Gmelin, 1791), is described and illustrated.

A new species of cyclopoid copepod belonging to the genus Lichomolgidium Kossmann 1877, which has been obtained from Pyura spinossisima from New Zealand, is described and illustrated.

The male of Doropygus platylhorax Jones, 1974 and two new species of Doropygus (D. louisae and D. spinosus) are described and illustrated. The specimens of Doropygus described by Schellenberg (1922) as D. pulex are assigned to the new species D. louisae. Specimens of Ophioseides (Scolecimorpha) joubini described by Schellenberg (1922) have been re‐examined together with fresh material, and have been described as a new species, Ophioseides schellen‐bergi.

The genus Hatschekia Poche, 1902 is reduced to 68 species. Interspecies variation is discussed, a key is given, and each species is illustrated. The following species are redescribed: Hatschekia albirubra Wilson, 1913; H. amplicapa Pearse, 1951; H. angulata Pearse, 1951; H. branchiostegi Yamaguti, 1939; H. breviramus Lewis, 1967; H. conifera Yamaguti, 1939; H. exigua Pearse, 1951; H. gerro Leigh-Sharpe, 1936; H. harkema Pearse, 1948; H. insolita Wilson, 1913; H. iridescens Wilson, 1913; H. ischnon Leigh-Sharpe, 1936; H. linearis Wilson, 1913; H. monacanthi Yamaguti, 1939; H. oblonga Wilson, 1913; H. ovalis (Bassett-Smith, 1898); H. parva Pearse, 1951; H. pinguis Wilson, 1908; H. prionoti Pearse, 1947; H. pygmaea T. Scott, 1913; H. quadrabdominalis Yu, 1933; H. uncata Wilson, 1913. The following are considered to be synonyms: H. crassa (Richiardi, 1879) for H. mulli; H. curvata Yamaguti & Yamasu, 1959 for H. quadrabdominalis; H. cylindrica Shiino, 1957 for H. branchiostegi; H. diodontis Yamaguti, ...

The pea crab Pinnotheres novaezelandiae Filhol (Brachyura: Pinnotheridac) infests the mussel Perna canaliculus (Gmelin) in Wellington Harbour. The crab passes through the same post‐planktonic stages as other pea crabs. The number of eggs hatching increases over summer, although females can be found incubating eggs at any time of the year. Shellfish below the level of low water neap tide are more heavily infested than those above this level. Damage to the host is restricted to erosion of the demibranchs and nodule formation on the mantle.

Samples of simple ascidians of the genera Asterocarpa, Cnemidocarpa, Corella, and Pyura were collected from Wellington Harbour, New Zealand (41°16'S, 174° 51'E) and three species of the crustacean family Notodelphyidae were recovered, all from the branchial baskets of the ascidians. Pygodelphys novaeseelandiae (Schellenberg), and two new species of Doropygus, are described and illustrated.

Populations of Paranephrops planifrons and P. zealandicus were reared in aquaria and their growth rates monitored. When reared in unheated aquaria (10–21°c) P. planifrons grew to 20 mm orbit‐carapace length in 12–18 months and P. zealandicus reached the same size in 9–10 months. This is faster, for both species, than in feral populations. When reared in an aquarium at 18–21°C however, P. planifrons could be grown to 35 mm orbit‐carapace length in 18 months. Mortality in both species was very high (60–93%).

This paper provides: a key to the species of New Zealand Caligus; a description of the male and female of Caligus kahawai n. sp., the female of C. longicaudatus Brady, 1899, and a redescription of female C. lalandei Barnard, 1948; the first records from New Zealand of C. bonito Wilson, 1905, and C. elongatus Nordmann, 1832; and further records of C. aesopus Wilson, 1921, C. brevis Shiino, 1954, C. buechlerae Hewitt, 1964, C. coryphaenae Steenstrup & Lutken, 1861, and C. pelamydis Kroyer, 1863.

The male of Abergasilus amplexus Hewitt, 1978 is described for the first time. Previous records of A. amplexus are discussed and a new locality, Te Whanga Lagoon, Chatham Islands, is reported.

Tergestia agnostomi Manter, 1954, recovered from the type host Aldrichetta forsteri (Guvier & Valenciennes, 1836) caught ait the type locality given by Manter, is redescribed from gravid specimens.

Spores of a new species of Nematopsis have been found in the green‐lipped mussel Perna canaliculus Gmelin. This is the first record of a sporozoan parasite of a New Zealand shellfish.

Microsporidian spores, identified as Thelohania sp., were recovered from muscle of Paranephrops planifrons White caught in Lake Taupo, New Zealand. This is a new host record for Thelohania. Variation in spore size with fixation and with time is noted. Mean live spore size differs from T. contejeani Henneguy described previously from P. zealandicus (White) in New Zealand, but falls within the range for European T. contejeani.