Do protandric pandalid shrimp have environmental sex determination?

Bergström, Bo

doi:10.1007/s002270050105

Cited by 33 publications

(18 citation statements)

References 6 publications

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“…Moreover, Bergström (1992Bergström ( , 1997 and Marliave et al (1993) have suggested that the varying frequencies of genotypes programming for sex-change at different ages/sizes in populations may affect the occurrence of EMFs in pandalid shrimps. Although the possible relationship between EMMs and EMFs still remains undescribed, juveniles that become EMFs need to grow more rapidly than other individuals of the same age group because EMFs have to pass through a size range in which they are not large enough to pro-duce eggs.…”

Section: Discussionmentioning

confidence: 99%

Factors affecting the occurrence of early maturing males in the protandrous pandalid shrimp Pandalus latirostris

Chiba

Goshima²,

Mizushima³

2000

Mar. Ecol. Prog. Ser.

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Some Age-0 males of the protandrous pandalid shrimp Pandalus latirostris Rathbun mature in their first year, and the proportion of these early maturing males (EMMs) in a population varies both locally and annually. Two laboratory experiments and 2 field observations were conducted to clarify the factors affecting the occurrence of EMMs. The first experiment showed that EMMs needed to grow fast until the breeding season and began producing sperm at about 14 mm carapace length. Individuals with an AMP (length of the endopod/length of the appendix masculina) value above 40 were defined as EMMs. In the second experiment, the effects of food amount, hatching date and maternal size on growth at Age-0 were examined. Food amount strongly affected the early growth. A difference in hatching date of > 2 wk caused a large difference in body size of juveniles; this difference was maintained until the breeding season 3 mo later. Large females spawned larger larvae than small females, but the size difference between larvae from large females and those from small females decreased with time. Field observations showed that at one site in Saroma Lagoon, Hokkaido, Japan, hatching occurred over a 1 mo period. In 1996/1997, we found no obvious differences of size distribution of Age-0 individuals and the occurrence of EMM as a function of location in the lagoon or year. These results may have been caused by slow growth, because water temperatures in the lagoon were much colder in 1996/1997 than during 1987 to 1995. We conclude that the occurrence of EMMs is closely related to various environmental factors in shallow waters. Therefore, the proportion of EMMs may fluctuate both locally and annually. This study shows that a small difference in juvenile growth over a short period can alter the subsequent life history of P. latirostris. KEY WORDS: Protandry · Pandalid shrimp · Growth · Maturity · Life history variationResale or republication not permitted without written consent of the publisher

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Section: Discussionmentioning

confidence: 99%

Factors affecting the occurrence of early maturing males in the protandrous pandalid shrimp Pandalus latirostris

Chiba

Goshima²,

Mizushima³

2000

Mar. Ecol. Prog. Ser.

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“…In at least one protandrous shrimp [30] and one protandrous limpet [31], there was no variation in size at sex change despite considerable shortterm variation in age structure and mortality rates within and between populations. The apparent absence of sexratio compensation following selective removal of males by fishing in some large protogynous fishes [32] suggests that they also have a relatively fixed size at sex change.…”

Section: Reviewmentioning

confidence: 93%

Diversity and flexibility of sex-change strategies in animals

Munday

Buston

Warner

2006

Trends in Ecology & Evolution

336

337

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Here, we review recent empirical advances that have improved our understanding of why and when sex change occurs. We show that sex-changing animals use a greater diversity of strategies to increase their reproductive success than was previously recognized: some individuals change sex early, others change sex late, some individuals change sex more than once, and others do not change sex at all. These different strategies can be unified by the principle that individuals change sex when it increases their reproductive value. The breeding tactics (male, female or non-breeder) adopted by individuals often appear to be adaptive responses to their own social-ecological context and variation in these conditions results in significant differences in the timing of sex change within and between species.

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“…In other words, as the mean size of breeding animals decreased, due to increased mortality of older breeders through fishing or environmental influences, the size at sex change also decreased. On the other hand, Bergström (1997) found no evidence that annual variation in age/size structure affected the time at sex change in P. borealis from enclosed fjordic populations; however, his study encompassed only a short time series. In view of the controversy surrounding size/age of sex change in Pandalid shrimp and its potential use as an indicator of stock status, we examined factors influencing sex change in the P. borealis stock on the Scotian Shelf.…”

Section: Introductionmentioning

confidence: 91%

Density Dependant Sex Change in Northern Shrimp, Pandalus borealis, on the Scotian Shelf

Koeller¹,

Mohn²,

Etter³

2000

J. Northw. Atl. Fish. Sci.

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We investigated factors affecting sex change in the Pandalid shrimp Pandalus borealis on the Scotian Shelf. Transition from male to female occurred at different sizes and ages, and could not be related to a minimum size or age. Our data did not show a positive relationship between abundance of older females and shrimp size at sex transition, nor a negative relationship between male:female sex ratio and shrimp size at transition, that would be expected if the population was compensating for decreases in reproductive capacity as predicted by sex allocation theory. Size at transition was inversely related to female density, which was attributable to density dependent growth affecting all stages. Density dependant growth also appeared to explain previously reported results which had been used to support sex allocation theory. Density was the most important factor determining individual growth at high densities while at low densities other factors, including temperature, were also an important determinant of growth. We conclude that a decrease in the size at transition can be indicative of a healthy, as well as a declining stock, and must be fully understood before it can be used as an indicator of stock status. Possible alternative mechanisms for regulating sex change in Pandalids are discussed.

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Do protandric pandalid shrimp have environmental sex determination?

Cited by 33 publications

References 6 publications

Factors affecting the occurrence of early maturing males in the protandrous pandalid shrimp Pandalus latirostris

Factors affecting the occurrence of early maturing males in the protandrous pandalid shrimp Pandalus latirostris

Diversity and flexibility of sex-change strategies in animals

Density Dependant Sex Change in Northern Shrimp, Pandalus borealis, on the Scotian Shelf

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