Sex Ratios and Distribution of Spawning King Crabs in Alitak Bay, Kodiak Island, Alaska (Decapoda Anomura, Lithodidae)

Powell, Guy C.; Gray, G. W.

doi:10.1163/156854066x00207

Cited by 15 publications

(10 citation statements)

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“…This males-directed selectivity may impose adverse effects on reproductive output since it causes difficulties in females finding mates. Similar cases were also found in crabs (Gray & Powell, 1966; Smith & Jamieson, 1991). Thus, in fishery management, the possible side effects of sex selection on reproductive success of the population should be considered (Zhou et al, 2010).…”

Section: Discussionsupporting

confidence: 80%

Reproductive pattern and population dynamics of commercial red swamp crayfish (Procambarus clarkii) from China: implications for sustainable aquaculture management

Jin

Jacquin

Xiong

et al. 2019

PeerJ

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BackgroundThe red swamp crayfish, Procambarus clarkii (Girard, 1852), is one of the most promising freshwater species for aquaculture in China. Understanding its reproductive pattern and population dynamics is crucial for sustainable management, but there is currently a lack of fundamental knowledge of commercial P. clarkii populations. Therefore, the purpose of this study was to investigate the reproductive pattern and population dynamics of commercial P. clarkii throughout the yearly cycle.MethodsA total of 2,051 crayfish (1,012 females and 1,039 males) were collected from March 2016 to February 2017 in the area of Selection and Reproduction Center of Crayfish. The reproductive pattern was evaluated by the gonadosomatic index (GSI), hepatosomatic index (HSI), ovarian development and fecundity. Growth, mortality rates and exploitation rate were estimated by electronic length frequency analysis by R package “TropFishR” based on data of cephalothorax length (CTL).ResultsOur results demonstrated that spawning activities of P. clarkii took place from September to November, with a mean fecundity of 429 ± 9 eggs per female. There were two recruitments yearly, a major one from October to November and a minor one from March to May. With respect to population growth, five growth cohorts were identified for both females and males. Crayfish grew faster but attained smaller asymptotic maximum CTL as indicated by higher growth coefficient (K), growth parameter index (Ø′) and lower asymptotic CTL (Linf). The estimates of total mortality rate (Z), natural mortality rate (M) and fishing mortality rate (F) were 1.93, 1.02, 0.91 year−1 for females and 2.32, 0.93, 1.39 year−1 for males, which showed that the mortality of male crayfish was mainly caused by fishing. The estimates of exploitation rate (E) indicated that male crayfish were overexploited, with the values of 0.47 and 0.60 year−1 for females and males, respectively.DiscussionP. clarkii spawned from September to November while two recruitments were observed yearly. We inferred that some eggs, prevented from hatching by low water temperature in winter, were more likely to hatch in the next spring. Moreover, the fishing mortality rate was relatively high for males, which might be related to the males-directed selection during the reproductive period. The higher values of exploitation rate in our study confirmed that males P. clarkii were overexploited and were under high fishing pressure. We thus suggest reducing fishing intensity on immature crayfish and avoid sex selection during the reproductive period to improve the overall sustainability of commercial P. clarkii populations.

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Section: Discussionsupporting

confidence: 80%

Reproductive pattern and population dynamics of commercial red swamp crayfish (Procambarus clarkii) from China: implications for sustainable aquaculture management

Jin

Jacquin

Xiong

et al. 2019

PeerJ

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“…Because a decrease in male crab density reduces the frequency of female encounters with males (Gray & Powell 1964, Powell et al, 1974, Ennis 1980, Smith & Jamieson 1991, females would tend to fail to mate within the limited sexually receptive period after molting in populations consisting of few small males. Smaller males may rapidly deplete their sperm reserve and thus the number of males available for mating would decrease progressively during the reproductive season.…”

Section: Discussionmentioning

confidence: 99%

“…A decrease in male crab density by male-only fishing reduces the frequency of female encounters with males and causes difficulty for females to find mates, as seen in some large decapod species (Gray & Powell 1964, Powell et al 1974, Ennis 1980, Smith & Jamieson 1991. In fished crab populations comprised of fewer males, males would deplete their sperm reserves because of the large number of successive matings.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Impacts of male-only fishing and sperm limitation in manipulated populations of an unfished crab, Hapalogaster dentata

Sato¹,

Goshima²

2006

Mar. Ecol. Prog. Ser.

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“…Despite the fact that larger males of the spiny king crab have a competitive advantage for females than smaller males (Wada et al 1997), even small males had many matings before being depleted, indicating a decrease in competition for possession of receptive females among remaining males; that is, an excessive decrease in male density in fished populations. Decreases in male density reduce the frequency of female encounters with potential male mates (Gray & Powell 1964, Powell et al 1974, Ennis 1980, Smith & Jamieson 1991, which would increase the probability that females fail to mate within the optimal duration after molting. Since spiny king crab females also have an optimal duration to mate and fertilize successfully after their molting (Sato et al 2005), the reproductive success of a fished population with an excessive decrease in male density may also be restricted by such a female reproductive characteristic.…”

Section: Discussionmentioning

confidence: 99%

Effects of male mating frequency and male size on ejaculate size and reproductive success of female spiny king crab Paralithodes brevipes

Sato¹,

Ashidate²,

Wada³

et al. 2005

Mar. Ecol. Prog. Ser.

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Potential sperm limitation in a fished population of the spiny king crab Paralithodes brevipes was investigated in controlled laboratory experimental and field studies. The laboratory experiments examined the effects of male size and mating frequency on their reproductive potential and the recovery rate of exhausted sperm. The spawning success and fertilization rate of females decreased as the male mating frequency increased. The effects of increased male mating frequency on the spawning success of females and fertilization rates differed between male size classes. Male size and mating frequency have great influences on sperm limitation. Males showed little capacity to regenerate sperm, increasing the likelihood of limited sperm supply to females in fished population with low numbers of males due to male-selective fishing regulations. The field studies examined the structure of a fished population of P. brevipes in Hamanaka, eastern Hokkaido, before and after a change in the fishery regulations that permitted smaller males to be harvested. The results showed that a change in the sex ratio occurred after the fishery regulations were introduced, skewing the population towards females. The results also showed a decrease in the mean male size in the fished population. The results also indicated that a significant percentage of males (42.2%) had depleted sperm reserves just after the reproductive season. Overall, the results indicate that sperm limitation could occur in this fished population of P. brevipes. These observations may warrant a review of the current fishing regulations, particularly the minimum legal size.

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Sex Ratios and Distribution of Spawning King Crabs in Alitak Bay, Kodiak Island, Alaska (Decapoda Anomura, Lithodidae)

Cited by 15 publications

References 1 publication

Reproductive pattern and population dynamics of commercial red swamp crayfish (Procambarus clarkii) from China: implications for sustainable aquaculture management

Reproductive pattern and population dynamics of commercial red swamp crayfish (Procambarus clarkii) from China: implications for sustainable aquaculture management

Impacts of male-only fishing and sperm limitation in manipulated populations of an unfished crab, Hapalogaster dentata

Effects of male mating frequency and male size on ejaculate size and reproductive success of female spiny king crab Paralithodes brevipes

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