Halibut Caught Research Articles

The use of artificial illumination to reduce Pacific halibut (Hippoglossus stenolepis) bycatch for a high-rise bottom trawl in the U.S. West Coast groundfish fishery

In the last decade, there has been increasing interest in the use of artificial illumination as a bycatch reduction device. In the U.S. West Coast groundfish bottom trawl fishery, research has found that the addition of green light-emitting diode (LED) lights to the upper bridles of low-rise cutback trawls significantly reduced Pacific halibut (Hippoglossus stenolepis) bycatch. Recent regulation changes in this fishery now permit high-rise trawls, a gear configuration with a higher vertical opening, in areas where only low-rise trawls were previously permitted. This study conducted catch comparison and catch ratio analyses to determine if catches of Pacific halibut and three commercially important groundfishes (e.g., petrale sole [Eopsetta jordani], Dover sole [Microstomus pacificus], and sablefish [Anoplopoma fimbria]) differ between illuminated and non-illuminated tows for a high-rise bottom trawl. Illuminated tows caught fewer individuals than the non-illuminated tows across all species, including Pacific halibut; however, the difference in catch efficiency was not significant. Total catch volume did have a significant positive effect on levels of glucose and lactate for Pacific halibut. However, no statistically significant differences between illuminated and non-illuminated tows were exhibited across all of the physiological parameters assessed. The results from our study provide valuable information to fishers and managers that can be used for future decision-making and identifying research priorities.

Biological characteristics of the Pacific halibut in the Bering Sea and off the eastern coast of Kamchatka in spring 2022

The purpose of the work: to give a biological characteristic of the Pacific halibut in different areas of the Bering Sea and off the eastern coast of Kamchatka and to analyze its size age composition in catches of trawl fishing. Methods used: the material was collected during the expedition research, a complete biological analysis of the Pacific halibut was carried out, the otoliths were selected to determine the age. The age was determined in accordance with the guidelines developed specifically for the Pacific halibut in the International Commission on Pacific Halibut (International Pacific Halibut Commission, IPHC).Novelty: the elements of novelty are generalized and analyzed data on Pacific halibut. The material collected in the waters of Eastern Kamchatka and the Bering Sea in 2022. Pacific halibut from trawl catches have been studied, its biological characteristics have been considered, the size-age composition and growth rate have been analyzed.Practical significance: the results of these studies can be used in forecasting the stocks of Pacific halibut in this area.Result: data on catches of Pacific halibut in different regions of the North West Pacific Ocean, the size and age composition, a comparative characteristic of males and females by growth rate, the age composition of fish by maturity stages.

Examining the evolution of access to Alaska's halibut IFQ fishery

In fishing communities, livelihoods and well-being depend on sustaining access to key fisheries through changes in natural resource management. In Alaska, the rationalization of the commercial fishery for Pacific halibut (Hippoglossus stenolepis) in 1995 led to the consolidation of the halibut fleet. The high cost of halibut catch shares have since become a crucial barrier to prospective entrants, especially small-scale operations with few options for portfolio diversification. However, quantitative approaches to understanding that barrier face an information gap: datasets on harvest and catch share ownership in fisheries lack common identifiers for individuals. We match individuals across harvest and catch share ownership data from 1991 through 2019, enabling a detailed examination of entrants and non-entrants – those who acquire or do not acquire halibut catch shares over the time series. We compare fisheries portfolios in terms of participation and earnings through duration, dissimilarity, and network analyses. Differences over time and between entrants and non-entrants emerge across analyses. For both groups, cohorts of participants shrink and real individual earnings increase over the time series. However, entrants' cohorts have decreased further relative to historical participation, while entrants' real earnings and fisheries portfolio compositions have diverged from those of non-entrants. Our results reveal broad differences in Alaska fisheries participants' access to a critical fishery, underscoring the role of catch shares in shaping fishing communities’ opportunities and resilience in the face of social and environmental change.

Bycatch in the California halibut (Paralichthys californicus) Trawl Fishery

Bycatch rates within the California halibut trawl fishery were calculated using landed catch data from 1997–2020 fishery logbooks and estimated using landed and discarded catches from 2002–2019 fishery observer data. Average bycatch rates were significantly different between the two datasets. The average bycatch ratio estimated from fishery logbooks was 0.36 ± 0.17 while the average bycatch ratio estimated from the observer data was 4.61 ± 1.29, based on the weight of bycatch to weight of California halibut catch. Additionally, the most frequently caught bycatch species were estimated for each dataset. Bycatch rates calculated from the observer data were closely aligned with fishery-independent surveys conducted by the California Department of Fish and Wildlife, signaling the importance of using fishery observers to obtain estimates of bycatch within the California halibut fishery. Spatial patterns of bycatch revealed that fishing effort was highest near Monterey, San Luis Obispo and Ventura. Our results suggest that data from logbooks alone are not sufficient to adequately estimate bycatch within the California halibut trawl fishery.

Use of the traditional halibut hook of the Makah Tribe, the čibu.d, reduces bycatch in recreational halibut fisheries.

A previous study found that use of the traditional halibut hook (čibu.d) of the Makah Tribe in present day recreational Pacific halibut (Hippoglossus stenolepis) fisheries significantly reduced bycatch compared to paired 8/0 circle hooks. The study also found that the čibu.d had a significantly reduced catch of halibut, but that the reduction may have been due to manufacturing flaws in the čibu.d used in the study. In this two-phased study, we first compared the fishing performance of redesigned čibu.d made from four different materials: brass, stainless steel, plastic, and wood. In the second phase, we compared the fishing performance of the brass čibu.d with two common recreational fishing set-ups: a single large 16/0 circle hook and paired 8/0 circle hooks. The fishing performance of the redesigned čibu.d was not statistically different for čibu.d made of brass, stainless steel, or plastic. However, the čibu.d made from wood had significantly lower catch of halibut than the other čibu.d. We selected the brass čibu.d for the second phase of the study for continuity with the previous study of čibu.d and found that it had significantly less bycatch and a lower bycatch ratio than both the paired 8/0 and single 16/0 circle hooks. No significant differences were found in catch rates of halibut for paired 8/0 circle hooks, 16/0 circle hook, and the brass čibu.d. This study demonstrates that the improved catching performance of čibu.d on halibut and reduced bycatch compared to other popular approaches can be achieved by using brass čibu.d. Managers of recreational halibut fisheries should consider the use of čibu.d in areas where bycatch is a concern.

Recreational Leasing of Alaska Commercial Halibut Quota: The Early Years of the GAF Program in Alaska

The Pacific Halibut Catch Sharing Plan formalized the process for allocating halibut between the Alaska commercial and recreational charter sectors. It included a new program intended to allow for “flexibility” through inter-sectoral trading, permitting charter operators to lease commercial halibut pounds to relax client harvest restrictions. Here we evaluate the first two years of lease market activity and participation. Participation from some commercial quota holders in the lease market suggests that the program provided beneficial flexibility; in fact, the number of transfers to the charter sector was greater than transfers within the commercial sector for some quota types. We also identified a high proportion of self-leasers. However, transfers to the charter sector were on average smaller than within-sector commercial transfers, and total poundage leased by the charter sector was low compared with commercial transfers. Usage of leased quota by the recreational charter sector enables the harvest of larger fish or additional fish, and provides flexibility in catch composition on halibut closure days. Finally, the value-per-pound may be higher in the charter sector, as commercial-to-charter transfer prices approached the commercial ex-vessel price.

Spatiotemporal bycatch analysis of the Atlantic halibut (Hippoglossus hippoglossus) longline fishery survey indicates hotspots for species of conservation concern

The Atlantic halibut (Hippoglossus hippoglossus) longline fishery is the second most valuable groundfish fishery in Atlantic Canada and received Marine Stewardship Council certification in 2013. The bottom longline fishery accounts for most halibut landings but incidentally catches nontargeted species (bycatch). Since 1998, Fisheries and Oceans Canada and the halibut fishing industry performed annual longline surveys across the Scotian Shelf and Southern Grand Banks stock management area to monitor halibut abundance, and at‐sea observers also recorded bycatch information. We examined the species composition and proportion of the survey bycatch and analyzed temporal and spatial trends in standardized weight of (a) halibut catch, (b) total bycatch, and (c) bycatch of species of conservation concern. From 1998 to 2016, 70% of the total catch by weight and 85% by number of individuals were bycatch. Over 100 identified species of finfish, sharks, skates, benthic invertebrates, marine mammals, and seabirds were caught as bycatch in the survey. This included four species listed under the Species at Risk Act (Northern wolffish, Anarhichas denticulatus; spotted wolffish, A. minor; Atlantic wolffish, A. lupus; Atlantic cod, Gadus morhua), and another 14 species awaiting a listing decision based on assessments by the Committee on the Status of Endangered Wildlife in Canada. Generally, the standardized weight of halibut and barndoor skate (Dipturus laevis) increased over time, while Atlantic cod, spiny dogfish (Squalus acanthias), white hake (Urophycis tenuis), and thorny skate (Amblyraja radiata) decreased. Spatial patterns indicated high bycatch levels on the southern Scotian Shelf and southern edge of the Southern Grand Banks, with hotspots for certain species of conservation concern. Our results identify temporal trends in threatened species and areas where they are susceptible to the Atlantic halibut longline fishery which can inform recovery strategies, bycatch levels and spatial zoning in fisheries management and marine conservation.

Testing of Two Selective Flatfish Sorting-Grid Bycatch Reduction Devices in the U.S. West Coast Groundfish Bottom Trawl Fishery

AbstractIn the U.S. West Coast limited-entry (LE) groundfish bottom trawl fishery, catches of stocks with restrictive harvest limits (e.g., Darkblotched Rockfish Sebastes crameri, Sablefish Anoplopoma fimbria, and Pacific Halibut Hippoglossus stenolepis) continue to hinder many fishermen’s ability to fully utilize their quota shares of more abundant flatfish stocks (e.g., Dover Sole Microstomus pacificus and Petrale Sole Eopsetta jordani). We used a recapture net to examine the size-selection characteristics of two selective flatfish sorting-grid bycatch reduction devices (BRDs), which were designed to reduce catches of Pacific Halibut and non-flatfish species while retaining target flatfishes. The two devices were identical in materials and design except that the sorting-grid dimensions differed (BRD-1: 6.4- × 25.4-cm grid size; BRD-2: 6.4- × 30.5-cm grid size). The size selectivity for rockfishes, other roundfishes, Pacific Halibut, English Sole Parophrys vetulus, and Rex Sole Glyptocephalus zachirus di...

Recreational Leasing of Alaska Commercial Halibut Quota: The First Two Years of the Guided Angler Fish Provision

The Pacific Halibut Catch Sharing Plan creates a process for allocating halibut between the Alaska commercial and recreational charter sectors. A provision intended to allow for “flexibility” creates an inter-sectoral trading market, permitting charter operators to lease commercial halibut pounds to relax client harvest restrictions. Here we evaluate the first two years of lease market activity and participation. We find the program may provide beneficial flexibility to some commercial quota holders, with the number of transfers to the charter sector being greater than transfers within the commercial sector for some types of commercial quota. We also identify a high proportion of self-leasers. However, transfers to the charter sector are on average smaller than within-sector commercial transfers, and total poundage leased by the charter sector is low compared to commercial transfers. Finally, the value-per-pound may be higher in the charter sector, as commercial-to-charter transfer prices approach the commercial ex-vessel price.

Evaluation of a sorting grid bycatch reduction device for the selective flatfish bottom trawl in the U.S. West Coast fishery

The U.S. West Coast limited entry groundfish trawl fishery is managed under an individual fishing quota program. For many fishermen targeting flatfishes in this fishery, catches of rockfishes (Sebastes spp.), sablefish (Anoplopoma fimbria), and Pacific halibut (Hippoglossus stenolepis) can be a concern because quota is limited relative to flatfish quotas. Thus, approaches to minimize bycatch of limiting species are important to the economic viability of the fishery. In this study, we examined the size-selection characteristics of a flexible sorting grid bycatch reduction device (designed to retain flatfishes while reducing catches of rockfishes, sablefish, and Pacific halibut) using a recapture net. The mean codend retention of target flatfishes (five species evaluated) ranged from 68.1% to 92.3%. Combined, the mean flatfish retention was 85.6%. Codend catches of shelf rockfishes, slope rockfishes, sablefish, and Pacific halibut were reduced by 80.3%, 64.0%, 97.0%, and 90.3% by weight, respectively. Significant differences in selectivity parameters between flatfishes, rockfishes, sablefish, and Pacific halibut were observed. Over fishing grounds where fishermen need a more selective trawl to harvest flatfishes, the experimental gear tested could provide fishermen a technique to reduce catches of non-target species.

Applying Bayesian spatiotemporal models to fisheries bycatch in the Canadian Arctic

Understanding and reducing the incidence of accidental bycatch, particularly for vulnerable species such as sharks, is a major challenge for contemporary fisheries management. Here we establish integrated nested Laplace approximations (INLA) and stochastic partial differential equations (SPDE) as two powerful tools for modelling patterns of bycatch through time and space. These novel, computationally fast approaches are applied to fit zero-inflated hierarchical spatiotemporal models to Greenland shark (Somniosus microcephalus) bycatch data from the Baffin Bay Greenland halibut (Reinhardtius hippoglossoides) gillnet fishery. Results indicate that Greenland shark bycatch is clustered in space and time, varies significantly from year to year, and there are both tractable factors (number of gillnet panels, total Greenland halibut catch) and physical features (bathymetry) leading to the high incidence of Greenland shark bycatch. Bycatch risk could be reduced by limiting access to spatiotemporal hotspots or by establishing a maximum number of panels per haul. Our method explicitly models the spatiotemporal correlation structure inherent in bycatch data at a very reasonable computational cost, such that the forecasting of bycatch patterns and simulating conservation strategies becomes more accessible.

Tradable permit programs: What are the lessons for the new Alaska halibut catch sharing plan?

To address long-standing allocation conflicts between the Pacific halibut commercial fishing sector and recreational charter (for-hire) sector in Alaska, an Alaska halibut catch sharing plan (CSP) is being implemented in 2014 that has a provision allowing the leasing of commercial individual fishing quota to recreational charter businesses. This one-way inter-sectoral trading allows for the charter sector to increase its share of the total allowable catch while compensating commercial fishermen. This type of catch shares program is novel in fisheries. In this paper, the literature on non-fisheries tradable permit programs (TPPs) that have similarities to the Alaska halibut CSP program is examined. Several successful TPPs are discussed, including ones from emissions trading programs, water quality trading programs, water markets, and transferable development rights programs. They are then evaluated in terms of their similarities and differences to the Alaska CSP program. Characteristics not part of the current CSP that other TPPs have used and that may increase the likelihood for the CSP to be effective in achieving its primary goals (if they are implemented) are identified, such as allowing more flexible transfers (e.g., internal transfers), intertemporal banking, cooperative structures, and multi-year leasing.

Occurrence of fungi from the genus Cryptococcus in diseases internal organs of the Greenland halibut

The purpose of this study was to establish if in the diseased internal organs of the Greenland halibut - mainly liver and kidney - it is possible to find <i>Cryptococcus</i> fungi and of the presence of these fungi corresponds with the pathologic changes in these organs. The incidence of <i>Cryptococcus</i> fung in the aquens of Labrador and New Founland in see fishes may be an index of these organismes in the sea water. Psychrophilie <i>Cryptococci</i> were found in the kidneys and livers of Greenland halibut caught in these regions. The presence may be correlated with the pathological changes found in these organs.

Circle Hook Size and Spacing Effects on the Catch of Pacific Halibut

Joint fishing for halibut (Hippoglossus stenolepis Schmidt, 1904) and sablefish (Anoplopoma fimbria Pallas, 1811) in Alaska in recent years has created questions about the use of fishing effort data in the halibut stock assessment. The optimum gear for halibut uses larger hooks and longer spacing than sablefish gear. We conducted a randomized block fishing experiment to estimate the relative fishing power of different hook sizes and spacings. The blocks consisted of 12 randomized treatments, each a combination of one of four hook sizes and four hook spacings. All possible treatments were not tested because some are not used in the fishery. Each treatment consisted of a single 100-hook skate of gear. Primary response variables were the weight of legal-sized halibut for commercial retention and the count of sub-legal sized fish. The experiment was conducted in a high fish density region in 2005 and in a lower fish density region in 2007. There was no evidence of an interaction effect between hook size and hook spacing in either year, for either legal-sized weight or sub-legal count. Hook size had an effect on sub-legal fish counts in both areas, with highest catches on smaller hooks, but there was evidence of a hook size effect on legal weight in the high density area. Hook spacing had an effect on weights and counts with higher catch seen on the longer spacings.

Age determination, bomb-radiocarbon validation and growth of Atlantic halibut (Hippoglossus hippoglossus) from the Northwest Atlantic

Atlantic halibut (Hippoglossus hippoglossus) is the largest and one of the most widely-ranging and commercially-valuable groundfish in the Atlantic Ocean. Although presumed to be long-lived, their age and growth has not been validated. Ages were estimated by counting growth increments from approximately 2400 thin-sectioned sagittal otoliths collected from the Scotian Shelf and southern Grand Banks off eastern Canada. The accuracy of age estimates made from otolith thin sections was validated using bomb-radiocarbon assays of 13 otolith cores whose year of formation ranged from 1949 to 1975, encompassing the timeframe of the global radiocarbon pulse. Known-age juvenile halibut from a culture facility were used to identify the approximate location of the first annulus. Growth rate for males and females was similar up to about 70 cm (~5 years), after which point male growth slowed, while female growth continued to an age of up to 38 years and a maximum observed size of 232 cm. Males grew to an observed maximum length of about 175 cm and a maximum age of 50 years. A comparison of age estimates for otoliths collected in a ‘historic’ time frame (1963 to 1974) with those from recent years (1997 to 2007) shows that growth rate has not changed appreciably between the two time periods. Small but significant growth differences were observed between the Scotian Shelf and southern Grand Banks for both sexes, while large differences in length at age were observed between halibut caught with longline compared to otter trawl due to differences in length-based gear selectivity. Age interpretations based on sectioned otoliths tended to be 10–15% different than those based on break and burn, although the age comparison was confounded by other variables and must be considered provisional. Atlantic halibut is a long-lived fish, living up to at least 50 years, an important consideration for the management of the fishery.

Field investigation of rare-earth metal as a deterrent to spiny dogfish in the Pacific halibut fishery

Spiny dogfish ( Squalus acanthias) comprise a significant unwanted bycatch on demersal longlines set for halibut, sablefish ( Anoplopoma fimbria), and Pacific cod ( Gadus macrocephalus) in shelf waters of the east and west coasts of North America. Recently, rare-earth magnets and metals have been shown to have deterrent effects on sharks. These effects are likely the result of magnetic or electric fields created by these materials in seawater, which are sensed and avoided by sharks. Our earlier laboratory studies showed that attack rates by spiny dogfish on baits protected with cerium mischmetal (a rare-earth alloy) were reduced and suggested that this metal might reduce unwanted bycatch of spiny dogfish in setline fishing for Pacific halibut ( Hippoglossus stenolepis). We conducted a field study near Homer, Alaska in September 2007 with three hook treatments interspersed on 36 longline sets. These included standard circle hooks used in the halibut fishery, hooks with small pieces of cerium mischmetal attached above the hook, and hooks with a similar (but inert) mild steel piece above the hook. Fewer dogfish were caught on hooks with mischmetal than on either of the two other treatments. Reductions in catch of longnose skate ( Raja rhina) also occurred on hooks protected with mischmetal. However, halibut catch did not increase with protected hooks. Limitations in using mischmetal in commercial operations are expense, hazardous nature, and relatively rapid hydrolysis in seawater.

Compensatory growth and fillet crude composition in juvenile Atlantic halibut: Effects of short term starvation periods and subsequent feeding

The aim of this study was to investigate the effects of short term starvation periods on growth response and fillet crude composition of juvenile halibut. Fish were fed to satiation twice a day or starved in four feeding schedules as follows; feeding (F) 99 days (Control); 11 days starvation (S), followed by 20 days F, 14 days S, 22 days F, 11 days S and 21 days F (Starvation A); 16 days S, 28 days F, 16 days S and 39 days F (Starvation B); 32 days S and 67 days F (Starvation C). Each tank contained 70 fish with an initial mean weight (SD) of 195.7 (46.6) g. All starvation groups showed partial compensation during re-feeding, displaying an increase in daily feeding rate and a tendency towards increased feed conversion efficiency compared to the control group. The length of the re-feeding periods was, however, insufficient to let the starved halibut catch up with the fish weight in the control group although growth rate in the last sampling period up to day 99 was significantly higher in the starvation groups than in the control group. The results indicated that the experiment was ended in a phase when the fish were still undergoing compensatory growth. The results further indicate that as much as 32 days of starvation and subsequent feeding does not affect the fillet composition of juvenile halibut.

The use of historical catch data to trace the influence of climate on fish populations: examples from the White and Barents Sea fisheries in the 17th and 18th centuries

Abstract We analysed catch records of Atlantic salmon (Salmo salar), cod (Gadus morhua), and halibut (Hippoglossus hippoglossus and Reinhardtius hippoglossoides) from the 17th and 18th centuries from several locations of the Barents and White Seas areas. Historical records, found in Russian archives, allow analysis of long-term series of catches, and sometimes of the average weight of the fish. In total, we obtained data on catches of salmon for 51 years (for the period from 1615 to 1772) and of cod and halibut for 33 years (for the period from 1710 to 1793). These data are comparable with respect to fishing effort within the series. The data on Atlantic salmon are also comparable with statistical data for the period 1875–1915. We found notable fluctuations in catches and sometimes in the average weight of salmon. There was also fluctuation in catches of cod and halibut. Both observational comparison of catch series and temperature data and formal statistical analysis showed that catches tended to decrease during relatively colder periods.

Catches of Greenland halibut ( Reinhardtius hippoglossoides) in deepwater ghost-fishing gillnets on the Norwegian continental slope

Fishing gear may continue to fish after it has been lost. Large catches have been observed during cruises to retrieve lost gillnets in Norwegian waters, especially in the fishery for Greenland halibut ( Reinhardtius hippoglossoides). The Norwegian Greenland halibut is overexploited, and there is serious concern about the effect of lost nets on this stock. Catches in deliberately lost gillnets were studied in the fishery for Greenland halibut off the coast of mid-Norway in July 2000 and June 2001. Gillnet fleets were deployed at depths of between 537 and 851 m, and the soak time ranged from 1 to 68 days. Most of the catch consisted of the target species, and the proportions of different species did not change with soak time. All individuals caught were categorized in terms of seven condition states. A gradual shift from fresh to decomposed individuals over time was evident. The catching efficiency of gillnets decreased with soak time, presumably due to the weight of the catch causing the headline height to decrease, and after 45 days was only about 20–30% of that of nets used in the commercial fishery. Catch rates were estimated after stabilization at 67–100 and 28–43 kg per day per gillnet fleet in 2000 and 2001, respectively. The results indicated that gillnets lost in this area continue to fish for long periods of time. Annual losses of nets need to be quantified in order to estimate the effects of ghost fishing on stock levels, a figure that is currently lacking.

Commercial deep water trawling at sub-zero temperatures – observations from the Faroe-Shetland channel

Commercial deep water trawling occurs north and west of Scotland on the continental slopes of the Faroe-Shetland channel (FSC) and the Rockall trough. From existing hydrographic knowledge, reported depths being fished in the FSC suggested that trawling was taking place in waters of zero or sub-zero temperatures. Fishing in deep water at these temperatures may be unique in terms of global commercial fisheries. Instrumentation of a Scottish deep water commercial trawler's net with a temperature and depth recorder showed that indeed some fishing time (<8%) was spent in sub-zero water. However, best catches of both Greenland halibut ( Reinhardtius hippoglossoides) and Roughhead grenadier ( Macrourus berglax) and most fishing time were associated with boundary waters in the range 0–4°C. Variable conditions on a seasonal or shorter time scale were demonstrated as were changes in ambient water temperature of almost 6°C during individual hauls. Sub-zero temperatures were recorded as shallow as 600 m whilst at the same depth modal haul temperature showed a range >6°C. The variable and much colder conditions of the deep water in the FSC were contrasted with the stable and warmer conditions of the Rockall trough. Further research is required if management of this growing fishery is to be scientifically based.