Effects of high pCO2 on Tanner crab reproduction and early life history—Part I: long-term exposure reduces hatching success and female calcification, and alters embryonic development

Abstract Ocean acidification, a decrease in ocean pH due to absorption of anthropogenic atmospheric CO2, has variable effects on different species. To examine the effects of long-term exposure on Tanner crab (Chionoecetes bairdi) embryonic development, hatching success, and calcification, ovigerous females were reared in one of three treatments: ambient pH (∼8.1), pH 7.8, and pH 7.5 for 2 years. Embryos and larvae in year 1 were from oocytes developed in the field and appear resilient to high pCO2. Embryos and larvae in year 2 were from oocytes developed under high pCO2 conditions. Oocyte development appears sensitive to high pCO2, effects carryover and altered embryonic development, and reduced hatching success with on average 71% fewer viable larvae hatched in the pH 7.5 treatment than in the other treatments. Per cent calcium was reduced among females exposed to pH 7.5 waters, and their carapaces were noticeably more pliable than those in the other treatments. Softer carapaces may result in reduced defences against predators, and a reduction in the ability to feed on prey with hard parts such as shells. The results from this long-term study suggest that projected ocean pH levels within the next two centuries will likely have a pronounced impact on Tanner crab populations unless the crab are able to acclimatize or adapt to changing conditions.

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Effects of long-term exposure to ocean acidification conditions on future southern Tanner crab (Chionoecetes bairdi) fisheries management

ICES Journal of Marine Science ◽

10.1093/icesjms/fsv205 ◽

2015 ◽

Vol 73 (3) ◽

pp. 849-864 ◽

Cited By ~ 12

Author(s):

André E. Punt ◽

Robert J. Foy ◽

Michael G. Dalton ◽

W. Christopher Long ◽

Katherine M. Swiney

Keyword(s):

Ocean Acidification ◽

Hatching Success ◽

Larval Survival ◽

Reference Points ◽

Juvenile Survival ◽

Natural Mortality ◽

Tanner Crab ◽

Larval Hatching ◽

Chionoecetes Bairdi

Abstract Demographic models of pre- and post-recruitment population dynamics were developed to account for the effects of ocean acidification on biological parameters that affect southern Tanner crab (Chionoecetes bairdi) larval hatching success and larval and juvenile survival. Projections of stock biomass based on these linked models were used to calculate biological and economic reference points on which fisheries management advice is based and thus provide fisheries managers with strategic advice on the likely long-term consequences of ocean acidification. The models utilized information for southern Tanner crab in the eastern Bering Sea. This information included the monitoring data on which conventional size-structured stock assessments are based, as well as the functional relationships that determine survival based on experiments that evaluated the consequences of ocean acidification over the next 100–200 years on crab larval hatching success, larval survival, and the survival of juvenile crab. The results highlighted that juvenile survival had the largest effect (∼20% decrease over 75 years) on biological and economic reference points, while hatching success, particularly if density dependence occurs after hatching, and larval survival have smaller effects (<10% decrease). Catch and profits would be expected to decrease by >50% in 20 years if natural mortality is affected by ocean acidification. Additional laboratory data on oocyte and embryo development leads to large changes in biological reference points depending on the timing of ocean acidification effects relative to natural mortality. The results highlight the need for experiments to evaluate the longer term physiological effects of ocean acidification on multiple life history stages and to measure indices that directly inform population dynamics models to evaluate future management scenarios.

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Reproductive Parameters and Productivity of the Yellow-Shouldered Parrot on Margarita Island, Venezuela: a Long-Term Study

The Condor ◽

10.1093/condor/108.1.178 ◽

2006 ◽

Vol 108 (1) ◽

pp. 178-192 ◽

Cited By ~ 1

Author(s):

Virginia Sanz ◽

Adriana Rodriguez-Ferraro

Keyword(s):

Clutch Size ◽

Human Disturbance ◽

Hatching Success ◽

Reproductive Potential ◽

Reproductive Investment ◽

Egg Laying ◽

Reproductive Parameters ◽

Term Study ◽

Long Term Study

AbstractWe studied the breeding biology of the Yellow-shouldered Parrot (Amazona barbadensis) on Margarita Island from March-August, 1990 to 1999. The timing of the different phases (egg-laying, hatching, fledging) was consistent over the years, except during 1998 when all phases were delayed. The average clutch size was 3.38 ± 0.78 eggs per nest, with a range of one to five eggs per clutch, and most eggs survived until hatching (3.36 ± 0.80 eggs per nest). Total clutch size and hatching success of this species on Margarita Island are among the highest in the genus Amazona, suggesting the Yellow-shouldered Parrot has a higher reproductive potential than other species of the genus. We detected interannual differences for some of the reproductive parameters, all in 1998, a year with an extreme drought. Egg losses totaled 20% and were caused by hatching failure, predation, and human disturbance. Forty-nine percent of nestlings were lost, mainly due to poaching. The number of fledglings per nesting pair averaged 1.27 ± 1.61, but varied greatly among years. Thus, in relation to the average total clutch laid, each pair lost an average of 62% of its initial reproductive investment.

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