scholarly journals Changes in habitat utilization of slope-spawning flatfish across a bathymetric gradient

2016 ◽  
Vol 73 (7) ◽  
pp. 1875-1889 ◽  
Author(s):  
Cathleen D. Vestfals ◽  
Lorenzo Ciannelli ◽  
Gerald R. Hoff
Keyword(s):  
Habitat Use ◽  
Environmental Variability ◽  
Effect Of Temperature ◽  
Greenland Halibut ◽  
Pacific Halibut ◽  
Eastern Bering Sea ◽  
Geographic Coverage ◽  
Hippoglossus Stenolepis ◽  
Greenland Halibut Reinhardtius Hippoglossoides ◽  
Ocean Environment

Abstract Understanding how fish distributions may change in response to environmental variability is important for effective management of fish populations, as predicted climate change will likely alter their habitat use and population dynamics. This research focused on two commercially- and ecologically-important flatfish species in the eastern Bering Sea (EBS), Greenland halibut ( Reinhardtius hippoglossoides ) and Pacific halibut ( Hippoglossus stenolepis ), which may be especially sensitive to climate-induced shifts in habitat due to strong seasonally and ontogenetically variable distributions. We analysed data from fishery-dependent and fishery-independent sources to determine how environmental variability influenced habitat use, thus gaining a uniquely comprehensive range of seasonal and geographic coverage of each species’ distribution. Greenland and Pacific halibut exhibited strong and contrasting responses to changes in temperature on the shelf, with catches decreasing and increasing, respectively, beyond 1 °C. The effect of temperature was not as prominent along the slope, suggesting that slope habitats may provide some insulation from shelf-associated environmental variability, particularly for Greenland halibut. With warming, Greenland halibut exhibited more of a bathymetric shift in distribution, while the shift was more latitudinal for Pacific halibut. Our results suggest that habitat partitioning may, in part, explain differences in Greenland and Pacific halibut distributions. This research adds to our understanding of how the distributions of two fish species at opposite extremes of their ranges in the EBS – Greenland halibut at the southernmost edge and Pacific halibut at the northernmost edge – may shift in relation to a changing ocean environment.

A mixed-species yield model for eastern Bering Sea shelf flatfish fisheries

2002 ◽  
Vol 59 (2) ◽  
pp. 291-302 ◽  
Author(s):  
Paul D Spencer ◽  
Thomas K Wilderbuer ◽  
Chang Ik Zhang
Keyword(s):  
Bering Sea ◽  
Optimal Solution ◽  
Single Species ◽  
Mixed Species ◽  
Yield Model ◽  
Pacific Halibut ◽  
Eastern Bering Sea ◽  
Hippoglossus Stenolepis ◽  
Hippoglossoides Elassodon ◽  
Trawl Fisheries

A variety of eastern Bering Sea (EBS) flatfish including yellowfin sole (Limanda aspera), rock sole (Lepidopsetta bilineata), flathead sole (Hippoglossoides elassodon), and Alaska plaice (Pleuronectes quadrituberculatus), co-occur in various degrees in EBS trawl fisheries, impeding attempts to obtain single-species management targets. A further complication is the bycatch of Pacific halibut (Hippoglossus stenolepis); halibut bycatch limits, rather than single-species catch quotas, have been the primary factor regulating EBS flatfish harvest in recent years. To examine bycatch interactions among the EBS flatfish listed above, an equilibrium mixed-species multifishery model was developed. Equilibrium yield curves, scaled by recent average recruitment, are flat topped or asymptotically increasing, reflecting low fishing selectivity during the first several years of life and low growth relative to natural mortality. A linear programming analysis indicated that relaxation of the halibut bycatch constraint at the optimal solution of catch by fishery would produce approximately 20 times more flatfish yield than a similar relaxation of any flatfish catch quota. A strategy for establishing halibut bycatch limits that considers the foregone revenue in the halibut and flatfish trawl fisheries reveals how the choice of halibut bycatch limit is affected by the management goal for the flatfish complex.

A new species of Entobdella Blainville in Lamarck, 1818 (Monogenea: Capsalidae: Entobdellinae) from the Greenland halibut, Reinhardtius hippoglossoides

2015 ◽  
Vol 60 (3) ◽  
Author(s):  
Graham Kearn ◽  
Egil Karlsbakk ◽  
Richard Evans-Gowing ◽  
Pavel Gerasev
Keyword(s):  
Ventral Surface ◽  
Molecular Techniques ◽  
Atlantic Halibut ◽  
Greenland Halibut ◽  
Gill Parasite ◽  
Pacific Halibut ◽  
Greenland Halibut Reinhardtius Hippoglossoides ◽  
Reinhardtius Hippoglossoides ◽  
The Relationship ◽  
Reproductive Apparatus

AbstractA previously undescribed species of Entobdella is reported from the skin of the Greenland halibut, Reinhardtius hippoglossoides (Pleuronectiformes, Pleuronectidae). Entobdella whittingtoni sp. nov. differs from other species of Entobdella, including skin parasites of the related pleuronectids Hippoglossus hippoglossus (Atlantic halibut) and H. stenolepis (Pacific halibut), in lacking papillae on the ventral surface of the haptor. Other characteristics of E. whittingtoni are as follows: the absence of vitelline follicles lateral to the pharynx thereby exposing gut caeca in this region of whole mounts; the presence of a circular feature of unknown function, resembling a rosette in sections, attached to the wall of the internal male accessory reservoir; the lack of eyes. Papillae are also absent from the ventral surface of the haptor of the gill-parasitic entobdelline Branchobdella pugetensis, a gill parasite of the pleuronectid Atheresthes stomias. This raises the question as to whether this gill parasite has evolved from a skin-parasitic ancestor similar to E. whittingtoni. An answer to this question requires a more detailed study of the male reproductive apparatus of B. pugetensis and the use of molecular techniques to explore the relationship between B. pugetensis and E. whittingtoni

scholarly journals Analysis of match–mismatch between commercial fishing periods and spawning ecology of Pacific halibut (Hippoglossus stenolepis), based on winter surveys and behavioural data from electronic archival tags

2011 ◽  
Vol 68 (10) ◽  
pp. 2240-2251 ◽  
Author(s):  
Timothy Loher
Keyword(s):  
Environmental Variability ◽  
Temporal Distribution ◽  
Seasonal Migration ◽  
Boreal Winter ◽  
Commercial Fishing ◽  
Pacific Halibut ◽  
Archival Tags ◽  
Hippoglossus Stenolepis ◽  
The Face ◽  
Opening And Closing

Abstract Loher, T. 2011. Analysis of match–mismatch between commercial fishing periods and spawning ecology of Pacific halibut (Hippoglossus stenolepis), based on winter surveys and behavioural data from electronic archival tags. – ICES Journal of Marine Science, 68: 2240–2251. The fishery for halibut (Hippoglossus stenolepis) in the eastern Pacific is closed during the boreal winter, roughly corresponding to the seasonal spawning of the species. Opening and closing dates for each season are stipulated annually based on economics and biology. Historical surveys and data from electronic tags are analysed to assess the extent to which recent closures have encompassed the annual spawning cycle of the species, as defined by migration to offshore spawning sites, active spawning, and return to feeding areas. These were assessed by calculating mean maximum daily depth profiles for fish exhibiting seasonal migration, calculating the date-specific proportions of the tagged population either migrating to or resident on their feeding or spawning grounds, and examining the temporal distribution of spent and running fish in historical surveys along with evidence of spawning contained in high-resolution tag data. The data indicate that fishery closures over the past 20 years have been consistently too short to protect the entirety of a migration period that begins as early as September and is not substantially completed until May. Additionally, some recent season openings have encroached on the active spawning season. Failure to fully protect spawning migrations may allow seasonal interception fisheries, and the selective removal of early and late spawners could cause changes in stock demographics, restrict effective spawning, and influence long-term stock productivity, especially in the face of environmental variability.

Serum Transferrin Systems and the Hemoglobins of the Pacific Halibut (Hippoglossus stenolepis)

1969 ◽  
Vol 26 (9) ◽  
pp. 2351-2362 ◽  
Author(s):  
H. Tsuyuki ◽  
E. Roberts ◽  
E. A. Best
Keyword(s):  
Bering Sea ◽  
Serum Proteins ◽  
Rare Type ◽  
Population Analyses ◽  
Pacific Halibut ◽  
Eastern Bering Sea ◽  
The Pacific ◽  
Hippoglossus Stenolepis ◽  
Northeastern Pacific ◽  
Starch Gel

Based on starch-gel electrophoretic analyses of serum proteins of 1092 specimens of Pacific halibut sampled from the eastern Bering Sea and northeastern Pacific Ocean southward to southern British Columbia, three molecular species of transferrins were encountered. A fourth rare type was postulated to explain the observation of some phenotypes involving this transferrin. These transferrins, either singly or in combinations of two, accounted for the theoretically possible 10 phenotypes of which 8 were actually observed. Hereditary control by four codominant alleles (TfA, TfB, TfC, and TfD) is postulated to explain the heterogeneity of the transferrin patterns. The collections were arbitrarily divided into 10 geographic areas and gene frequency analyses were used to determine population structure. Phenotypic distribution was shown to be independent of age and sex. Of the 10 areas, only the collection from southeastern Alaska proved not to be homogeneous. Preliminary analysis of blood hemoglobins indicated that these proteins are not of value in population analyses.

scholarly journals Evidence for rapid avoidance of rockfish habitat under reduced quota and comprehensive at-sea monitoring in the British Columbia Pacific halibut fishery

2020 ◽  
Vol 77 (8) ◽  
pp. 1409-1420
Author(s):  
Robyn E. Forrest ◽  
Ian J. Stewart ◽  
Cole C. Monnahan ◽  
Katherine H. Bannar-Martin ◽  
Lisa C. Lacko
Keyword(s):  
British Columbia ◽  
Spatial Clustering ◽  
Clustering Methods ◽  
Quota System ◽  
Encounter Rates ◽  
System A ◽  
Pacific Halibut ◽  
Hippoglossus Stenolepis ◽  
Footprint Area ◽  
Management Changes

The British Columbia longline fishery for Pacific halibut (Hippoglossus stenolepis) has experienced important recent management changes, including the introduction of comprehensive electronic catch monitoring on all vessels; an integrated transferable quota system; a reduction in Pacific halibut quotas; and, beginning in 2016, sharp decreases in quota for yelloweye rockfish (Sebastes ruberrimus, an incidentally caught species). We describe this fishery before integration, after integration, and after the yelloweye rockfish quota reduction using spatial clustering methods to define discrete fishing opportunities. We calculate the relative utilization of these fishing opportunities and their overlap with areas with high encounter rates of yelloweye rockfish during each of the three periods. The spatial footprint (area fished) increased before integration, then decreased after integration. Each period showed shifts in utilization among four large fishing areas. Immediately after the reductions in yelloweye rockfish quota, fishing opportunities with high encounter rates of yelloweye rockfish had significantly lower utilization than areas with low encounter rates, implying rapid avoidance behaviour.

scholarly journals Reproductive strategy, egg characteristics and embryonic development of Greenland halibut (Reinhardtius hippoglossoides)

2012 ◽  
Vol 70 (2) ◽  
pp. 342-351 ◽  
Author(s):  
Rosario Domínguez-Petit ◽  
Patrick Ouellet ◽  
Yvan Lambert
Keyword(s):  
Embryonic Development ◽  
Reproductive Strategy ◽  
Biochemical Composition ◽  
Incubation Temperature ◽  
Life Stage ◽  
Early Life Stage ◽  
Greenland Halibut ◽  
Hatching Time ◽  
Greenland Halibut Reinhardtius Hippoglossoides ◽  
Reinhardtius Hippoglossoides

Abstract Domínguez-Petit, R., Ouellet, P., and Lambert, Y. 2013. Reproductive strategy, egg characteristics and embryonic development of Greenland halibut (Reinhardtius hippoglossoides). – ICES Journal of Marine Science, 70: 342–351. Despite the commercial importance of Greenland halibut (GH), important gaps exist in our knowledge of the reproductive and early life stage biology for this species. The present study examined through laboratory experiments the spawning strategy, realized fecundity, egg characteristics, biochemical composition, and embryonic development of GH. The results confirmed the hypothesis that GH is a single-batch spawner producing large eggs, resulting in low realized fecundity. Embryonic development and hatching time are highly dependent on incubation temperature; 50% hatching occurred after 46, 30, and 24 days at 2, 4, and 6°C, respectively. Few changes in the biochemical composition of the eggs are observed during embryonic development. Newly hatched larvae are not well developed, having a large yolk sac, no pigmentation and incomplete development of the jaws. Egg specific density confirmed the mesopelagic distribution of the eggs at sea. However, important buoyancy changes occurring in the last 3–4 days before hatching indicate that larvae hatch higher in the water column. These results are important for understanding advection and dispersion processes of GH eggs and larvae and the connectivity between spawning grounds and nursery areas.

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