scholarly journals Bycatch in a Commercial Lobster Fishery: Effects on Two Benthic Predators, Sea Raven and Longhorn Sculpin

2020 ◽  
Vol 12 (2) ◽  
pp. 113-123
Author(s):  
Brooke N. Anderson ◽  
Amelia M. Weissman ◽  
Brett Sweezey ◽  
John Mandelman ◽  
David B. Rudders ◽  
...  
1969 ◽  
Vol 47 (6) ◽  
pp. 1367-1380 ◽  
Author(s):  
Jiří Lom ◽  
Marshall Laird

Trichodina elizabethae n. sp. (which is commonly hyperparasitized by the suctorian Endosphaera engelmanni Entz), T. galyae n. sp., and T. domerguei (Wallengren) saintjohnsi n. subsp. are described from Newfoundland waters; the first two from the radiated shanny and lumpfish respectively, and the last from the mailed sculpin, lumpfish, and shorthorn sculpin. T. jarmilae n. sp. parasitizes the sea raven in the Bay of Fundy, New Brunswick. In both provinces, T. cottidarum Dogiel, sensu lato, occurs on shorthorn and longhorn sculpins. Two species of fish from brackish pools (the threespine stickleback in both areas; the mummichog in the Bay of Fundy) are often heavily parasitized by T. tenuidens Fauré-Fremiet. All the ciliates referred to were collected from the gills of their hosts, only two of which bore peritrichs other than trichodinids. One of these, Caliperia brevipes Laird, is found on the little skate in the Bay of Fundy and has been described elsewhere. The other, Scyphidia arctica Zhukov, is now reported from the longhorn sculpin in Newfoundland. Only five (16%) of 31 species of marine fish from Newfoundland bore trichodinids, as compared with nine (35%) of 26 from New Brunswick. However, four of the latter group had extremely light or sporadic infestations. Three of the rest, showing high incidence and heavy to extremely heavy infestations, were sculpins (Cottidae), as were three of the five Newfoundland hosts. Thus, while information is accumulating to suggest that marine fish trichodinids find optimum environmental conditions where mean seawater temperatures are not extreme (neither very warm nor very cold), certain fish are evidently more prone to infestation than others. This may well be due to varying ecological vulnerability to parasitization rather than to the operation of host specificity, an important question which, like that of environmental tolerances, merits early experimental attention. The paper includes a list of 61 species of Trichodina and the closely related Tripartiella and Trichodinella now known from marine and euryhaline fish, their validity being assessed on the basis of technique and the taxonomic criteria used.


1966 ◽  
Vol 23 (3) ◽  
pp. 341-347 ◽  
Author(s):  
F. W. H. Beamish

Endurance was determined in relation to swimming speed and temperature for Atlantic cod, Gadus morhua Linnaeus, redfish, Sebastes marinus (Linnaeus), winter flounder, Pseudopleuronectes americanus (Walbaum), and to swimming speed at 8 C for longhorn sculpin, Myoxocephalus octodecimspinosus (Mitchill), sea raven, Hemitripterus americanus (Gmelin), and ocean pout, Macrozoarces americanus (Block and Schneider).In an activity chamber at a swimming speed of 4 body lengths per second (BL/sec) Atlantic cod swam for about equally long periods at 5 and 8 C, and redfish and winter flounder each about equally long at 5, 8, and 11 C. The pattern was similar for higher speeds. At 14 C winter flounder swam longer at 6 BL/sec than at the lower temperatures. For swimming speeds less than 4 BL/sec all species swam longer at the higher temperatures. At 8 C, the only temperature at which all species were tested, endurance at comparable swimming speeds was greatest for winter flounder, followed by cod, redfish, longhorn sculpin, ocean pout, and sea raven.


1989 ◽  
Vol 46 (2) ◽  
pp. 191-197 ◽  
Author(s):  
J. S. Scott

Numbers of co-occurrences of 29 common fishes of the Bay of Fundy and Scotian Shelf were derived from annual research trawl survey data for the summers of 1970–79 and the spring, summer, and autumn seasons of 1980–84. Matrices prepared from the data were used to examine degrees of association between different species and seasonal and geographical variation in the associations. Three categories of associations were identified: shallow water with a dominant winter flounder (or yellowtail flounder) – longhorn sculpin – sea raven assemblage; middepth with a dominant cod – haddock – thorny skate assemblage; deepwater characteristic species but with no strong recurring assemblages. Strength of co-occurrence was directly related to species abundance and changes corresponded to known seasonal movements in several species, including silver hake, spiny dogfish, and pollock. In general, the strength and number of co-occurrences decreased from southwest to northeast along the Scotian Shelf. The Bay of Fundy was exceptional, with strong co-occurrences of shallow-water species and poor representation of deepwater fishes.


1982 ◽  
Vol 60 (6) ◽  
pp. 1326-1330 ◽  
Author(s):  
Terry D. Beacham

The length at which 50% of the individuals were mature was calculated for some Northwest Atlantic groundfish species. Median length at maturity for halibut (Hippoglossus hippoglossus) on the Scotian Shelf declined from 84 cm for males during 1959–1964 to 66 cm during 1970–1979. Median lengths at maturity for females declined from 98 to 70 cm. Ranges of median lengths (centimetres) at maturity for other species were as follows: cusk (Brosme brosme), male 48–56, female 47–56; longhorn sculpin (Myoxocephalus octodecemspinosus), male 24–29, female 23–25; ocean pout (Macrozoarces americanus), male 45, female 28; and sea raven (Hemitripterus americanus), male 36, female 28.


1992 ◽  
Vol 49 (10) ◽  
pp. 2062-2069 ◽  
Author(s):  
David J. Marcogliese ◽  
Gary McClelland

We examined larvae of the seal parasites Corynosoma wegeneri and Pseudoterranova decipiens in various fish species collected from Western and Sable Island banks between February 1989 and October 1990. Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), American plaice (Hippoglossoides platessoides), yellowtail flounder (Pleuronectes ferrugineus), windowpane (Scophthalmus aquosus), longhorn sculpin (Myoxocephalus octodecemspinosus), and sea raven (Hemitripterus americanus) were infected by both parasites, longhorn sculpin being a new host record for C. wegeneri. Only C. wegeneri occurred in winter flounder (Pleuronectes americanus), and neither parasite was found in northern sand lance (Ammodytes dubius) or capelin (Mallotus villosus). The two parasites were most numerous in sea raven and longhorn sculpin. Corynosoma wegeneri was more prevalent in fish sampled in 1989–90 than in previous surveys of Atlantic cod and haddock from the Scotian Shelf. Pseudoterranova decipiens and C. wegeneri occurred throughout the sampling area, but small fishes in the vicinity of Sable Island had the heaviest sealworm infections, and both parasites in longhorn sculpin declined with distance from Sable Island. Increases of C. wegeneri in groundfish, like recent increased levels of P. decipiens infection on the Scotian Shelf, can be attributed to the dramatic growth of the grey seal (Halichoerus grypus) population on Sable Island.


2003 ◽  
Vol 18 (2) ◽  
pp. 195-203 ◽  
Author(s):  
RALPH E. TOWNSEND ◽  
SAMUEL G. POOLEY ◽  
RAYMOND CLARKE

2015 ◽  
Vol 72 (5) ◽  
pp. 1555-1564 ◽  
Author(s):  
Rafael León ◽  
Caleb Gardner ◽  
Ingrid van Putten ◽  
Klaas Hartmann

AbstractEffective individual transferable quotas (ITQ) systems rebuild stocks and allow transfer of quotas to more efficient operators. This process requires functional markets for both quota sales and temporary quota leases. These markets are expected to respond to changes in economic rent from the fishery, which is influenced by stock abundance and the international rock lobster price. This research used multistate Markov modelling and Granger causality test to examine changes in the permanent and temporary quota trade in the Tasmanian rock lobster fishery quota market, during periods of both increasing and decreasing stock abundance. The permanent quota trade market was more active during the period of stock growth, while the quota lease market was active in both periods of stock growth and decline. In contrast to theoretical trends in ITQ fisheries, trades in both markets were not linked to the technical efficiency (i.e. catching capability) of operators, but were more driven by the quota owners' financial capacity (i.e. number of owned quotas). Prolonged and unexpected stock decline affected the quota market so that it deviated from the theoretical pattern of ITQ fisheries. Operators previously active in the market reduced their activity, while smaller operators and firms that previously had not traded became more active, so the fleet expanded with smaller operators entering.


1994 ◽  
Vol 72 (2) ◽  
pp. 247-251 ◽  
Author(s):  
R. A. Khan ◽  
D. E. Barker ◽  
K. Williams-Ryan ◽  
R. G. Hooper

Samples of longhorn sculpin (Myoxocephalus octodecemspinosus) were exposed to sediment contaminated with crude oil or pulp and paper mill effluent for periods up to 13 months in the laboratory. Other samples were collected at sites where crude oil or effluent from a pulp and paper mill are discharged. The intensity of gill infections of Trichodina spp. on exposed fish was significantly higher than on controls 5, 9, and 13 months after exposure. The intensity of the ciliates was also greater on sculpins collected near an oil-receiving terminal than on those sampled 5 km from the polluted site. Field collections of longhorn and shorthorn (Myoxocephalus scorpius) sculpins at and distant from a pulp and paper mill had high and low intensities of the ciliates, respectively. Similarly, the intensity of trichodinid ciliates was also significantly greater in longhorn sculpins exposed to effluent-contaminated sediment than in controls 5 months after exposure. The results suggest that the intensity of gill-inhibiting species such as trichodinids in susceptible fish hosts increases after chronic exposure to crude oil and to pulp and paper mill effluent, and the parasites may serve as indicators of pollution.


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