Are Density-dependent Effects on Elasmobranch Maturity Possible?

Sosebee, Katherine A.

doi:10.2960/j.v35.m492

Cited by 42 publications

(39 citation statements)

References 8 publications

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“…The growth parameter estimates suggested a greater asymptotic length and lower k value for female sharks when based on the VIMS1983 data set than when based on the VIMS2004 data set (Table 1). Few studies have shown significant changes in growth among K-selected species (Sminkey and Musick 1995;Carlson and Baremore 2003;Sosebee 2005;Cassof et al 2007). This is the fourth study involving elasmobranchs to demonstrate changes in growth rates following exploitation.…”

Section: Discussionmentioning

confidence: 99%

Compensatory Growth of the Sandbar Shark in the Western North Atlantic Including the Gulf of Mexico

Romine

Musick²,

Johnson³

2013

Mar Coast Fish

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The number of Sandbar Sharks Carcharhinus plumbeus in the western North Atlantic Ocean has experienced a drastic decline since the early 1980s, reaching a minimum during the early 1990s. Catch rates in the early 1990s were a mere 25% of those during the 1980s. According to several fishery‐independent surveys, the low point in Sandbar Shark abundance followed a period of high exploitation. Growth models fit to age–length data collected from 1980 to 1983 and from 2001 to 2004 were compared to investigate potential changes in parameter estimates that might reveal compensatory responses in the Sandbar Shark population. Statistical differences were found between the model parameters for the two time periods, but the differences in growth rates were minimal. The parameters from the three‐parameter von Bertalanffy growth model for female sharks during the 1980–1983 and 2000–2004 time periods were as follows: L∞ = 188.4 and 178.3 cm FL; k = 0.084 and 0.106; and t 0 = −4.097 and −3.41. For males the growth parameters were as follows: L∞ = 164.63 and 173.66 cm; k = 0.11 and 0.11; and t 0 = −3.62 and −3.33. The estimated age at 50% maturity for female Sandbar Sharks changed from 15 years to 12.49 years between the two time periods. Received December 21, 2012; accepted March 28, 2013

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Section: Discussionmentioning

confidence: 99%

Compensatory Growth of the Sandbar Shark in the Western North Atlantic Including the Gulf of Mexico

Romine

Musick²,

Johnson³

2013

Mar Coast Fish

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“…For example, increases in juvenile growth rates of two sharks, Sandbar Shark Carcharhinus plumbeus and Atlantic Sharpnose Shark Rhizoprionodon terraenovae, were documented after a drastic reduction in adult biomass in the 1980s (Sminkey and Music 1995;Carlson and Baremore 2003). In addition, Sosebee (2005) described a 9-cm decline in size at first maturity in female Spiny Dogfish Squalus acanthias in the U.S. northwest Atlantic Ocean after significant biomass declines in their respective adult populations. Although limited, the aforementioned studies indicate that compensatory changes can occur in shark species.…”

Section: Discussionmentioning

confidence: 99%

“…Atlantic Ocean (van der Lingen et al 2006). Although most research has focused on teleosts, evidence for density-dependent change has been documented in a few elasmobranchs after commercial exploitation had occurred (Sminkey and Music 1995;Carlson and Baremore 2003;Sosebee 2005). For example, increases in juvenile growth rates of two sharks, Sandbar Shark Carcharhinus plumbeus and Atlantic Sharpnose Shark Rhizoprionodon terraenovae, were documented after a drastic reduction in adult biomass in the 1980s (Sminkey and Music 1995;Carlson and Baremore 2003).…”

Section: Discussionmentioning

confidence: 99%

“…Conversely, an increasing population with an elevated density can respond with a reduced growth rate and increasing age and size at maturity (Rose et al 2001). Although such density-dependent changes have been widely documented in teleost fishes, they have been observed in only a few exploited shark species and never documented in a batoid (Sminkey and Music 1995;Carlson and Baremore 2003;Sosebee 2005). Given the recent changes in the biomass of Barndoor Skate, this species offers a unique opportunity to investigate potential density-dependent changes in life history characteristics in a skate species.…”

Section: Growth and Maturity Of Barndoor Skate 261mentioning

confidence: 99%

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Indication of Density‐Dependent Changes in Growth and Maturity of the Barndoor Skate on Georges Bank

Coutré

Gedamke²,

Rudders

et al. 2013

Mar Coast Fish

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Drastic increases or decreases in biomass often result in density‐dependent changes in life history characteristics within a fish population. Acknowledging this phenomenon and in light of the recent biomass increase in Barndoor Skate Dipturus laevis, the current study re‐evaluated the growth rate and sexual maturity of 244 specimens collected from 2009–2011within closed areas I and II on Georges Bank, USA. Ages were estimated using vertebral band counts from skate that ranged from 21 to 129 cm TL. The von Bertalanffy growth function was applied to pooled age‐at‐length data. Parameter estimates from the current study of L∞ = 155 cm TL and k = 0.10 represent a significant decrease from previously reported parameters of L∞ = 167 cm TL and k = 0.14. In addition to changes in growth parameters, age at 50% maturity for both males (based on clasper length, testes mass, and percent mature spermatocytes) and females (based on data from shell gland mass, ovary mass, and follicle diameter) increased by 3 years and 4 years, respectively. Based on our results and the 10‐ to 12‐year gap in the collection of samples, it is likely that Barndoor Skate within this region have exhibited pliability in life history parameters.Received January 21, 2013; accepted July 9, 2013

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“…While estimates of median size at maturity are crucial to fisheries stock assessments, these may change both spatially and temporally owing to environmental factors, population density or patchy fishing pressures (Rochet 2000;Sosebee 2005;Walker 2007). Regional differences in size at maturity have been noted for several species of elasmobranchs (Templeman 1987;Yamaguchi et al 2000;Lombardi-Carlson et al 2003).…”

Section: Introductionmentioning

confidence: 99%

A comparison of reproductive parameters of the Bering skate, Bathyraja interrupta, from two Alaskan large marine ecosystems

Ainsley

Ebert

Cailliet

2011

Mar. Freshwater Res.

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Abstract. Estimates of size at maturity are crucial to fisheries stock assessments and may change spatially and temporally. This study directly compares life-history characteristics of a skate species in two large marine ecosystems in a region where there is both a directed fishery and considerable skate by-catch in other fisheries. The Bering skate, Bathyraja interrupta, is one of the most common skate species in Alaskan waters, occurring in two large marine ecosystems, the eastern Bering Sea (EBS) and the Gulf of Alaska (GOA), but little is known about its life history. Skates were sampled from both regions between 2004 and 2007. In the GOA, the size at maturity was estimated to be 69 cm total length (TL) for males and 71 cm TL for females, while in the EBS size at maturity was estimated as 70 cm and 72 cm TL for males and females, respectively. Median size at maturity differed by sex but not by region. Our results indicate that B. interrupta shows late maturity, typical of most skate species, suggesting that more detailed monitoring of skate populations and precautionary management is warranted as skate fisheries expand.

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Are Density-dependent Effects on Elasmobranch Maturity Possible?

Cited by 42 publications

References 8 publications

Compensatory Growth of the Sandbar Shark in the Western North Atlantic Including the Gulf of Mexico

Compensatory Growth of the Sandbar Shark in the Western North Atlantic Including the Gulf of Mexico

Indication of Density‐Dependent Changes in Growth and Maturity of the Barndoor Skate on Georges Bank

A comparison of reproductive parameters of the Bering skate, Bathyraja interrupta, from two Alaskan large marine ecosystems

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