Shortnose sturgeon: Difference between revisions

The history of the shortnose sturgeon exploitation goes back 4,000 years.<ref | name=sturgeon_a>National Marine Fisheries Service. (2020) [https://www.fisheries.noaa.gov/species/shortnose-sturgeon]. </ref> [[Indigenous peoples of the Americas|Native American]] fishermen harvested shortnose and Atlantic sturgeon for their meat and eggs. This continued with the [[Jamestown, Virginia|Jamestown]] settlers in 1607 who utilized sturgeon as the primary food source for survival. Profitable fishery business using shortnose sturgeon began to grow in the 1800s leading to a rapid decline of the species population and distribution. By the late-1800s, sturgeon were being over-exploited. In 1890, over 7 million pounds of sturgeon were harvested in 1 year and as a result, in 1920, only 23,000 pounds of sturgeon were caught. Today, the shortnose sturgeon is in danger of extinction throughout its range and was listed as endangered under the [[Endangered Species Act]] on March 11, 1967.<ref | name=2020_biological_assessment_of_shortnose_sturgeon_b>National Oceanic and Atmospheric Administration. (2010). [https://repository.library.noaa.gov/view/noaa/17811 Five Year Plan for the Shortnose Sturgeon (''Acipenser brevirostrum'')].</ref> Shortnose sturgeon are protected in accordance with Section 1(c) of the Endangered Species Preservation Act of October 15, 1966 (80 Stat. 926: 16 U.S.C. 668aa(c)) after consulting the States, interested organizations and individual scientists, and finding that it was threatened with extinction. The [[IUCN]] has listed the shortnose sturgeon as a vulnerable species in 2004 with increasing action plans needed.<ref | name=shortnose_sturgeon_acipenser_brevirostrum>The Red List of Threatened Species. (2004) [https://www.iucnredlist.org/species/222/13036088] |title=Shortnose Sturgeon |author= Friedland, K.D. |author= Kynard, B. |accessdate=2020-04-15 |year=2004 </ref>

Historically, shortnose sturgeon were found in the coastal rivers along the East Coast of North America. Living from the [[Saint John River (Bay of Fundy)|Saint John River]] in New Brunswick all the way to the [[Indian River (Florida)|Indian River]] in Florida. Currently, shortnose sturgeon can be found in 41 bays and rivers along the East Coast. Their distribution across this range is broken up, with a large gap of about 250 miles separating the northern and mid-Atlantic metapopulations from the southern metapopulation. <ref | name=sturgeon_b>National Marine Fisheries Service. (2020) [https://www.fisheries.noaa.gov/species/shortnose-sturgeon]. </ref> There has been a shift slightly with lower sturgeon levels in river systems particularly further south. Modern spawning locations for the sturgeon include areas such as the Saint John River, [[Bay of Fundy]], and the [[Altamaha River]] with noticeable absences in North Carolina rivers.

Shortnose sturgeon live in rivers and coastal waters that run from Canada to Florida. Because shortnose sturgeon are [[amphidromous]] fish, after spawning most of their time is spent in estuaries and rivers. Shortnose sturgeon rarely spend time in the [[Atlantic Ocean]]. However, if the sturgeon do enter marine waters to feed or migrate they stay close to the shore. Shortnose sturgeon are more likely to move through all areas of a river system. Times they remain at sites for an extended period of time include resting and feeding periods.<ref | name=Occurrence_and_distribution_of_shortnose sturgeon_Acipenser_brevirostrum_,_in_the_upper_tidal_Delaware_River> Estuaries. (1987) [https://doi.org/10.2307/1351892] |title=Shortnose Sturgeon |author=Hastings, R.W. |author=O’Herron, J.C. |author=Schick, K. </ref>

Potential predators of the shortnose sturgeon include alligators, sharks, and other large fish such as [[catfish]]. Other known ones include [[sea lampreys]] gar, [[striped bass]], [[common carp]], [[northern pikeminnow]], [[channel catfish]], smallmouth bass, [[yellow perch]], walleye, grey seal, [[fallfish]], and [[sea lions]].<ref | name=2020_biological_assessment_of_shortnose_sturgeon_d>National Oceanic and Atmospheric Administration. (2010). [https://repository.library.noaa.gov/view/noaa/17811 Five Year Plan for the Shortnose Sturgeon (''Acipenser brevirostrum'')].
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Shortnose sturgeon spawn in moving freshwater water, over rubble or gravel bottoms. Time of spawning varies by latitude and is likely based on water temperatures in the range from 6.5–15  °C; this may be as early as January in South Carolina or as late as May in Canada. The eggs hatch after 13 days, into 7– to 11-mm-long hatchlings with a large yolk sac, minimal sight, minimal swimming ability, and a strong tendency to seek cover. After another 9–12 days, they mature to a swimming larval stage at about 15  mm in length, resembling a miniature adult by the time they reach 20  mm in length and begin feeding. They then drift downstream in the deep channels of the river, remaining in freshwater for the first year of their lives. Juveniles, up to 18 in long, generally move to brackish water, and move with it through the tidal cycle.

Adults mature sexually around 18 to 22 inches in length. Males mature after 2–3 years in their warmest habitats or 10–14 years in colder climates, and females mature between 6 and 17 years of age (again, earlier in southern rivers). Adults continue to grow to between 3 and 4  ft in length. A male may breed every year or every other year and seldom lives beyond age 30. Females usually breed every third to the fifth year, lying between 40,000 and 200,000 eggs when they breed and can live to age 67. Females spend multiple years with reduced feeding and growth while they are producing the gonadal material needed for spawning.

Although there are now about 12,000 adult shortnose sturgeon living within the Delaware River estuary, the population faces serious human-induced threats.<ref | name=Shortnose_Sturgeon_The_Delaware_River> Conserve Wildlife Foundation of New Jersey. (2020) [http://www.conservewildlifenj.org/species/spotlight/sturgeon/] |author=Bowers-Altman, Jeanette </ref> Water quality contaminants such as endocrine distributing chemicals (EDCs) have been linked to reproductive and developmental disorders in many fish species. These contaminants were found in shortnose sturgeon tissue collected in 2001 and include PCDDs/TCDFs, DDE, PCBs, and cadmium. Other threats to Delaware River shortnose sturgeon include heavy industrialization and waterfront development. This destruction of habitat can affect the Sturgeon’s ability to travel to freshwater and spawn or can degrade the quality of the habitat.<ref | name=sturgeon_c>The Red List of Threatened Species. (2004) [https://www.iucnredlist.org/species/222/13036088] |title=Shortnose Sturgeon |author= Friedland, K.D. |author= Kynard, B. |accessdate=2020-04-15 |year=2004 </ref> For example, some dams impede sturgeon travel back and forth between salt and fresh water, resulting in the disruption of natural spawning cycles and preventing the reproduction of the already struggling species.

More human-induced threats include ship/boat strikes, [[poaching]], mortality from commercial and recreational fishing (bycatch) due to high sensitivity to being caught, injury to early life stages from water intake systems, instream construction projects within the spawning area, and dredging, including the ongoing Delaware River deepening project.<ref | name=Sensitivity_of_North_American_sturgeons_and_paddlefish_to_fishing_mortality> Sturgeon Biodiversity and Conservation. (1996) [https://doi.org/10.1007/0-306-46854-9_28] |author= Boreman J. </ref> Additional research has been done to prove that [[algal blooms]], which can be caused by increased nitrogen levels in runoff or other anthropogenic factors, sometimes result in Shortnose Sturgeon die-offs.<ref | name=Saxitoxin_exposure> Marine Ecology Progress Series. (2012) [https://doi.org/10.3354/meps09768] |author=Fire, Spencer E. </ref> Overall, the combination of human-induced destruction of habitat and overconsumption have devastated many species along the Atlantic Coast. The future effects of climate change are not fully understood, however, these could potentially exacerbate many of these struggling populations even further.

Conservation efforts for the shortnose sturgeon include removing outdated dams from their habitats. The most recent recovery plan was enacted in December 1998, for the National Marine Fisheries Service National Oceanic and Atmospheric Administration. The stated goal of this plan is to recover populations to levels of abundance at which they no longer require protection under the ESA. For each population segment, the minimum population size will be large enough to maintain genetic diversity and avoid extinction.<ref | name=2020_biological_assessment_of_shortnose_sturgeon_e>National Oceanic and Atmospheric Administration. (2010). [https://repository.library.noaa.gov/view/noaa/17811 Five Year Plan for the Shortnose Sturgeon (''Acipenser brevirostrum'')].
</ref> NOAA Fisheries work with conservation organizations, energy companies, states, tribes, and citizens to evaluate barriers—big and small—to improve upon fish passage.

After listing the Shortnose Sturgeon as an endangered species in 1967, the 1998 Recovery Plan was enacted. The goal was to delist shortnose sturgeon populations throughout their range. The plan listed actions that if followed could restore the populations by the year 2024. Each of the population segments could become a candidate for downlisting when it reached a minimum population size that: 1) is large enough to prevent extinction, and 2) will make the loss of genetic diversity unlikely. This minimum population size for each population segment had not yet been determined.<ref | name=Final_recovery_plan> National Oceanic Atmospheric Administration. (1998) [https://repository.library.noaa.gov/view/noaa/15971] </ref>

To achieve and preserve minimum population sizes for each population segment, essential habitats were identified and maintained, and mortality, monitored and minimized. This plan has since been outdated and replaced.

This review concluded that the shortnose sturgeon still requires conservation efforts to support populations. The species is still at high risk under the IUCN and ESA listings.<ref | name=2020_biological_assessment_of_shortnose_sturgeon_f>National Oceanic and Atmospheric Administration. (2010). [https://repository.library.noaa.gov/view/noaa/17811 Five Year Plan for the Shortnose Sturgeon (''Acipenser brevirostrum'')].
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* {{FishBase species | genus=Acipenser | species=brevirostrum | month=February | year=2009}}