Management and Recovery Options for Ural River Beluga Sturgeon

Abstract

Management of declining fisheries of anadromous species sometimes relies heavily on supplementation of populations with captive breeding, despite evidence that captive breeding can have negative consequences and may not address the root cause of decline. The beluga sturgeon (Huso huso), a species threatened by the market for black caviar and reductions in habitat quality, is managed through harvest control and hatchery supplementation, with an emphasis on the latter. We used yield per recruit and elasticity analyses to evaluate the population status and current levels of fishing and to identify the life-history stages that are the best targets for conservation of beluga of the Ural River. Harvest rates in recent years were four to five times higher than rates that would sustain population abundance. Sustainable rates of fishing mortality are similar to those for other long-lived marine species such as sharks and mammals. Yield per recruit, which is maximized if fish are first harvested at age 31 years, would be greatly enhanced by raising minimum size limits or reducing illegal take of subadults. Improving the survival of subadult and adult females would increase population productivity by 10 times that achieved by improving fecundity and survival from egg to age 1 year (i.e., hatchery supplementation). These results suggest that reducing mortality of subadults and adult wild fish is a more effective conservation strategy than hatchery supplementation. Because genetics is not factored into hatchery management practices, supplementation may even reduce the viability of the beluga sturgeon.

Testing the Effectiveness of an International Conservation Agreement: Marketplace Forensics and CITES Caviar Trade Regulation

“…While some species appear to be less susceptible to illegal sale in the US market, others are now more vulnerable. Unfortunately, the conservation status of many sturgeon species has not improved since CITES listing, with most commercially traded species now Critically Endangered [33] and many, such as beluga, currently being overfished [34]. Limiting fishing in range states and further curtailing trade will be necessary to allow depleted sturgeon populations to recover.…”

Indicators of unsustainable fishery in the Middle Danube

“…; Doukakis et al. ) that avoids the need to estimate intrinsic population rate of increase, which is a parameter that is particularly difficult to reliably approximate (Jennings et al. ; Cheung et al.…”

“…Similarly, data on the survival of the eggs-to-age-1 age class were missing, and survival rates that produced no population growth (k = 1) were applied, which correspond to the population at equilibrium. This represents a standard approach for elasticity analysis parameterisation (Gross et al 2002;V elez-Espino et al 2006;Doukakis et al 2010) that avoids the need to estimate intrinsic population rate of increase, which is a parameter that is particularly difficult to reliably approximate (Jennings et al 1998;Cheung et al 2005). Moreover, such approach also provides a more standardised comparison among species.…”

The need for genetic support in restocking activities andex situconservation programmes: the case of the Adriatic sturgeon (Acipenser naccariiBonaparte, 1836) in the Ticino River Park

“…Maintaining the offspring of wild brood‐stock until maturity in the hatchery as future captive brood‐stock ( ex situ conservation) is considered a potentially useful strategy, widely applied in past decades. In a correct strategy proposed for conservation management of threatened species, every ex situ population must be investigated genetically to determine if it is a representative sample of the available genetic diversity (Russell and Amato, ; Doukakis et al., ; Theodorou and Couvet, ; Christie et al., ) and managed with the aim of maximizing its adaptive success after release (Ludwig, ; Kozfkay et al., ) in adequate target environments.…”

“…Some past sturgeon rehabilitation programmes were conducted without an adequate genetic management plan, employing a limited number of breeders in restoration activities of declining populations (Hayes et al., ; Doukakis et al., ), with a potentially detrimental effect on the residual genetic diversity of the remnant wild stocks.…”