The influence of ocean warming on the natural mortality of marine fishes

Author(s):  
Paige E. L. Levangie ◽  
Paul J. Blanchfield ◽  
Jeffrey A. Hutchings
2017 ◽  
Vol 284 (1856) ◽  
pp. 20170693 ◽  
Author(s):  
Jeffrey A. Hutchings ◽  
Anna Kuparinen

Probability of species recovery is thought to be correlated with specific aspects of organismal life history, such as age at maturity and longevity, and how these affect rates of natural mortality ( M ) and maximum per capita population growth ( r max ). Despite strong theoretical underpinnings, these correlates have been based on predicted rather than realized population trajectories following threat mitigation. Here, we examine the level of empirical support for postulated links between a suite of life-history traits (related to maturity, age, size and growth) and recovery in marine fishes. Following threat mitigation (medium time since cessation of overfishing = 20 years), 71% of 55 temperate populations had fully recovered, the remainder exhibiting, on average, negligible change (impaired recovery). Singly, life-history traits did not influence recovery status. In combination, however, those that jointly reflect length-based mortality at maturity, M α , revealed that recovered populations have higher M α , which we hypothesize to reflect local adaptations associated with greater r max . But, within populations, the smaller sizes at maturity generated by overfishing are predicted to increase M α , slowing recovery and increasing its uncertainty. We conclude that recovery potential is greater for populations adapted to high M but that temporal increases in M concomitant with smaller size at maturity will have the opposite effect. The recovery metric documented here ( M α ) has a sound theoretical basis, is significantly correlated with direct estimates of M that directly reflect r max , is not reliant on data-intensive time series, can be readily estimated, and offers an empirically defensible correlate of recovery, given its clear links to the positive and impaired responses to threat mitigation that have been observed in fish populations over the past three decades.


2005 ◽  
Vol 39 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Richard M. Starr ◽  
Victoria O'Connell ◽  
Stephen Ralston ◽  
Laurence Breaker

Advances in electronic telemetry systems have led to fish tagging studies that are sufficiently long to provide estimates of natural mortality of many marine fishes. We used acoustic transmitters and an array of recording receivers to estimate natural mortality, residence times, and rates of movements of lingcod (Ophiodon elongatus) in a marine reserve in southeast Alaska. We surgically implanted acoustic tags in a total of 83 lingcod in December 1999 and July 2000, and distributed recording monitors with receiving ranges of at least 800 m throughout the reserve. The receivers were anchored on the seafloor in locations that resulted in overlapping receiving ranges, and thus created an array of receivers that completely encompassed an 8 km2 reserve. In this way, we were able to estimate natural mortality rates and track movements of tagged lingcod into and out of the reserve from December 1999 through October 2001. Acoustic tag results indicated that most of the tagged fish frequently left the reserve, but were only absent for short time periods. Tagged fish showed a high degree of site fidelity. The large number of signals received from tagged fish enabled us to generate models that provided a way to predict the effects of marine reserves on yield and eggs per recruit for a cohort of female lingcod.


2020 ◽  
Vol 79 (3) ◽  
pp. 175-192
Author(s):  
AP Dineshbabu ◽  
PU Zacharia ◽  
T Sujitha ◽  
JK Shoba ◽  
KM Rajesh ◽  
...  
Keyword(s):  

2013 ◽  
Vol 26 (1 (special Issue)) ◽  
pp. 78-98
Author(s):  
Furhan T. Mhaisen ◽  
Najim R. Khamees ◽  
Atheer H. Ali
Keyword(s):  

Author(s):  
Katya Peycheva ◽  
Katya Peycheva ◽  
Mona Stancheva ◽  
Mona Stancheva ◽  
Stanislava Georgieva ◽  
...  

In this study, the ecosystem marine water-sediment-biota was investigated and the pollution was assessed. The concentrations of eight elements were determined in marine water, sediments and four fish species collected from Black Sea (Varna), Bulgaria during 2013. Marine water recorded the highest concentrations of Zn (15-22 μg/L), As (1.1–1.2 μg/L) and Pb (0.7-0.8 μg/L) while Zn (31-52 μg/g), Pb (21-29 μg/g) and Cu (20-34 μg/g) and show the highest concentrations in sediments. Water and sediments showed similar spatial distribution patterns for the highest mean values of the different metals. In the analysed fish species, the highest concentration of the metals Cu and Zn were found in Trachurus Mediterrneus (0.42 mg/kg w.w) and in Sprattus Sprattus (12.7 mg/kg w.w), respectively while the heavy metals As and Hg were found with maximum values in Pseta Maxima (3.99 mg/kg w.w and 0.08 mg/kg w.w respectively). The results from this study were compared with our data for a previous period (2004-2006) and they show decrease in the levels of heavy metal.


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