Movement, Mortality, and Size Selectivity of Sport- and Trawl-Caught Lingcod off Washington

Jagielo, Thomas H.

doi:10.1577/1548-8659(1999)128<0031:mmasso>2.0.co;2

Cited by 7 publications

(5 citation statements)

References 14 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Selectivity peaked at age-1 for all lakes under all scenarios except Lake Johns which exhibited decreasing relative selectivity with age when assumed age-0 survival was high. These results corroborate other selectivity studies (Jagielo, 1999;Bayley and Austen, 2002;McInerny and Cross, 2006) and indicate the trawl gear may be most useful for tracking small-sized black crappie through time. Individual selectivity estimates from our analyses should be viewed with caution, but the overall pattern of dome-shaped selectivity probably describes the general pattern of bottom trawl selectivity for black crappie and other similar-sized fishes.…”

Section: Discussionsupporting

confidence: 89%

Direct and indirect estimates of black crappie size selectivity to a common sampling gear: Potential biases and limitations for assessment

et al. 2009

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 89%

Direct and indirect estimates of black crappie size selectivity to a common sampling gear: Potential biases and limitations for assessment

et al. 2009

View full text Add to dashboard Cite

“…Mortality is very high in discarded fish with a gas bladder or organs which inflate after capture, while mortality may be variable and sometimes quite low in fish that do not have a gas bladder, or have a gas bladder that does not inflate after capture (Alverson et al 1994). While the mortality of discarded lingcod from trawl fisheries has been hypothesized, estimates of this mortality are not available (Jagielo 1999). The intent of this work was not to precisely duplicate widely varying fishing conditions and estimate bycatch mortality rates.…”

mentioning

confidence: 97%

Mortality of Lingcod Towed in a Net as Related to FishLength, Seawater Temperature, and Air Exposure: ALaboratory Bycatch Study

Davis

Olla

2002

North American Journal of Fisheries Management

View full text Add to dashboard Cite

The mortality of discarded bycatch is a critical problem in the management of fisheries worldwide. Little is known about the key principles involved in the mortality of discarded bycatch. These principles are best elaborated under controlled conditions in the laboratory where the actions and interactions of stressors found in fishing practices can be investigated independently. The goal of this study was to investigate the principles involved in the mortality of lingcod Ophiodon elongatus by testing hypotheses concerning the factors that may control trawl bycatch mortality. Lingcod were towed in a net and exposed to increased seawater temperature and to air, two stressors that occur during the processes of trawl capture, retrieval through a thermocline, and landing on deck. Mortality occurred after exposure to more than 45 min in air, after exposure to 4 h towing in a net followed by more than 30 min in air, or after 4 h towing followed by exposure to seawater above 16.0°C for 30 min and air for 15 min. In treatments of equal stressor intensity, smaller fish (41–51 cm total length) had higher rates of mortality than larger fish (52–67 cm). The effects of net towing and air—as well as of towing, increased seawater temperature, and air—were additive. Lingcod bycatch mortality may be reduced by decreasing trawling times and exposure to increased seawater and air temperatures during warmer seasons or by restricting fisheries that produce bycatch to seasons of cooler temperatures. The sorting, handling, and release of bycatch on deck after capture may be conducted in a manner that would probably enhance survival if fish are released within 30 min of capture. Because smaller lingcod had higher rates of mortality, further information about the mortality rates of relevant size‐classes of fish is needed to validate the assumptions of management rules for released, undersized bycatch that are designed to enhance recruitment.

show abstract

“…One hooking mortality study that examined recreational fishing mortality in California found very low levels of mortality after fish were held in tanks for several weeks (Albin and Karpov 1998). Consequently, their postrelease survival is thought to be generally good in recreational fisheries (Jagielo 1995(Jagielo , 1999. However, the vast majority of lingcod discards occur in the commercial bottom trawl fishery (PFMC 1999), and mortality rates for that gear type have never been estimated and so cannot be incorporated into stock assessment models (Jagielo et al 1997(Jagielo et al , 2000.…”

mentioning

confidence: 99%

Discard Mortality of Trawl-Caught Lingcod in Relation to Tow Duration and Time on Deck

Parker

Rankin

Hannah

et al. 2003

North American Journal of Fisheries Management

View full text Add to dashboard Cite

The lingcod Ophiodon elongatus is a benthic marine fish commonly caught by groundfish trawlers and discarded due to low catch limits. Managers must account for the mortality of bycatch to assess population status accurately. Our objectives were to estimate the actual mortality of trawl-discarded lingcod (50-84 cm) and describe their physiological stress response to capture. We investigated three major factors of the trawling operation that may influence lingcod survival: tow duration, fish size, and the amount of time fish were on the deck of the vessel. Survival was monitored for 21 d and each surviving animal was then physically and physiologically evaluated. The results showed that regardless of the duration of the tow, lingcod survival was 100% for animals discarded immediately after the cod end was emptied on deck. All lingcod captured during a tow of average commercial duration demonstrated a maximal stress response, measured by plasma cortisol, glucose, and lactate concentrations. As expected, lingcod from an average duration tow showed decreased survival with increased time on deck, though still had 50% survival after 30 min. This study suggests that discard mortality of lingcod is determined mainly by on-deck sorting and can be minimized by releasing fish quickly upon capture. Accurate estimation of mortality rates for lingcod will depend on the documentation of normal fishing behavior and on-deck sorting procedures.

show abstract

Movement, Mortality, and Size Selectivity of Sport- and Trawl-Caught Lingcod off Washington

Cited by 7 publications

References 14 publications

Direct and indirect estimates of black crappie size selectivity to a common sampling gear: Potential biases and limitations for assessment

Direct and indirect estimates of black crappie size selectivity to a common sampling gear: Potential biases and limitations for assessment

Mortality of Lingcod Towed in a Net as Related to FishLength, Seawater Temperature, and Air Exposure: ALaboratory Bycatch Study

Discard Mortality of Trawl-Caught Lingcod in Relation to Tow Duration and Time on Deck

Contact Info

Product

Resources

About