Welcome to FIS   Sponsored By
Subscribe to FIS | Register with FIS | Advertise with FIS | Newsletter | About FIS | Contact us
   


A juvenile southern flounder from Mill Creek in the southern region of a recent North Carolina State University study.Credit: NCSU

Warmer water linked to higher proportion of male flounder (sole)

Click on the flag for more information about United States UNITED STATES
Monday, May 13, 2019, 09:00 (GMT + 9)

If southern flounder (Paralichthys lethostigma) live in warmer water during a critical window of early development, a higher percentage become male -- more than 90 percent in some cases -- research from North Carolina State University found. Having a high proportion of adult males over the long term could threaten both wild populations and the valuable commercial fishing industry, which depends on larger female flounder.

Field research and lab experiments showed that a four-degree Celsius difference in average water temperature during juvenile development shifted the male-female ratio from about 50-50 to as much as 94-6, says Jamie Honeycutt, an NC State postdoctoral researcher and lead author of an article about the research in Scientific Reports. That difference is within the range of expected ocean temperature increases under climate change models.

Environmental factors such as water temperature influence sex determination in southern flounder, as well as in other fish and reptiles, Honeycutt explains. Flounder stick to shallow waters that serve as nurseries until after they become male or a female, hanging around estuaries until reaching maturity before returning to the ocean to spawn at about age 2.

"We think that southern flounder have a genetic sex-determining system similar to humans, who have two X chromosomes for a female and an X and a Y for a male. In flounder, if an individual is a genetic male, it is destined to be male," Honeycutt says. "However, if a genetic female is exposed to temperature extremes, then it can develop as a functioning male."

Native Range: Marine. Atlantic coastal and estuarine waters of the United States from Albemarle Sound, North Carolina, to Jupiter Inlet, Florida, and from Caloosahatchee estuary, Florida, to northern Mexico. South Florida is not included in the range (Lee et al. 1980 et seq.; Boschung 1992). Murdy et al. (1997) reported it as an occasional visitor to lower Chesapeake Bay, Virginia. | nas.er.usgs.gov

Environmental sex determination could allow flounder to do better under adverse conditions by producing more males, which are smaller and use fewer resources. But if the male bias persists in adult flounder, that could be bad news for wild populations and commercial and recreational fishing.

"Flounder fisheries are really totally dependent on females because males rarely make it to catch and market sizes," Honeycutt says. "Whenever you're eating a flounder in a restaurant, it is almost always a female flounder. So, the concern is that if populations are masculinized there will be fewer females to produce new flounder, further stressing this female-dependent fishery."

Paralichthys lethostigma(Southern Flounder) | NOAA - SEFSC Pascagoula Laboratory

From 2014 to 2017, researchers monitored spring and summer water temperatures in three regions: along Pamlico Sound (the northern region), the Neuse River (an intermediate zone) and Mill Creek (the southern region).

Sites in the northern region, where the average water temperature was 23 degrees Celsius, produced the greatest proportion of female flounder, closest to an even number of males and females. Those in the southern region, where the average water temperature was 27 degrees Celsius, had up to 94 percent male flounder. Proportions in the intermediate zone fell in between, showing a temperature gradient from north to south.

Because of the small size of juvenile flounder, scientists used a molecular biomarker developed from previous NC State research to determine sex. A follow-up experiment duplicated those conditions in tanks.

"What we wanted to do was mimic those temperature profiles in the laboratory when everything else was held constant to see if we could produce similar sex ratios," Honeycutt says. "And that's exactly what we found."

Average annual water temperature from representative juvenile southern flounder habitats in years 2015, 2016, and 2017 (April 16 to June 30). Temperature was recorded every 2 hours and readings were averaged for each 24-hour period. Letters indicate differences among habitats over the three years taken together (ANOVA, P < 0.0001). With all habitats combined the effect of year was significant for 2016 (ANOVA, *P < 0.0001).

Researchers were not able to track flounder through the life cycle in the wild to confirm that the biased sex ratios persist.

"One thing we can't say is exactly how this translates into changes in the adult population, because flounder move around a lot following juvenile development," says co-author John Godwin, an NC State biological sciences professor. "However, the southern flounder fishery has been listed in 'concerned' status for many years, so anything we can do to improve management tools and help it recover will be valuable."

Southern flounder is North Carolina's most valuable finfish, and it and related species are important coastal species in the Atlantic and Pacific, says co-author Russell Borski, an NC State biological sciences professor.

"We want to track the southern flounder population along the north-south gradient across the Southeast United States to see what's happening to the entire population, in Georgia and South Carolina versus North Carolina. We want to see whether the species is able to adapt to rising water temperatures by shifting its habitat."

Story Source: Materials provided by North Carolina State University | sciencedaily.com


Journal Reference:

  1. J. L. Honeycutt, C. A. Deck, S. C. Miller, M. E. Severance, E. B. Atkins, J. A. Luckenbach, J. A. Buckel, H. V. Daniels, J. A. Rice, R. J. Borski, J. Godwin. Warmer waters masculinize wild populations of a fish with temperature-dependent sex determinationScientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-42944-x

[email protected]
www.fis.com


 Print


Click to know how to advertise in FIS
MORE NEWS
Norway
Jul 17, 20:40 (GMT + 9):
Fish Pool Salmon Price Status Report for week 29
Ecuador
Jul 17, 18:00 (GMT + 9):
Shrimp exports reached a record high in the first 5 months of this year
Viet Nam
Jul 17, 17:00 (GMT + 9):
The sector must acquire technology to process fish if it wants to comply with its growth plans
Yemen
Jul 17, 17:00 (GMT + 9):
EU support to the Yemeni fisheries sector
Peru
Jul 17, 02:50 (GMT + 9):
Strong growth of landings and exports of squid foreseen after reopening of Chinese market
United Kingdom
Jul 17, 02:00 (GMT + 9):
IPNLF & ISSF launch first practical reference guide for pole-and-line fishing
Albania
Jul 17, 01:30 (GMT + 9):
Oceana denounces potential UII fishing across the Mediterranean Sea
New Zealand
Jul 17, 01:00 (GMT + 9):
Mussel farm granted permission to expand despite neighbours’ opposition
Japan
Jul 17, 00:30 (GMT + 9):
Official data on bluefin tuna imports
Worldwide
Jul 17, 00:00 (GMT + 9):
Situation and movements of fishmeal and fish oil
Ecuador
Jul 16, 23:50 (GMT + 9):
Manta will export 70pc of tuna production thanks to arrival of container ships
United Kingdom
Jul 16, 22:30 (GMT + 9):
UK Parliament's sub-committee warns of lack of implementation of EU discard ban
Worldwide
Jul 16, 19:20 (GMT + 9):
IN BRIEF - Global Fish Processing Market 2019-2025 Pelagia, Leroy, Pescanova, Maruha Nichiro, Thai Union
Canada
Jul 16, 19:00 (GMT + 9):
IN BRIEF - Norwegian company brings innovative fishing gear to Nova Scotia’s waters
Japan
Jul 16, 19:00 (GMT + 9):
IN BRIEF - Japanese longliner on fire, Indian ocean



Lenguaje
FEATURED EVENTS
  
TOP STORIES
Brexit Party MEP called for EU fishing vessels to be 'sunk like Belgrano'
United Kingdom A Brexit Party MEP has called for the Royal Navy to sink EU fishing vessels that enter a 200 mile exclusion zone around the United Kingdom. The policy would see EU boats as far away as France's Bay o...
Ocean Fish to acquire controlling interest in business partner
United Kingdom The Directors  of  Ocean Fish (Vistgate Limited) have  reached  an  agreement  with W Stevenson & Sons Limited to acquire a controlling interest in the business...
Minister of Economy vows to mull postponing giant squid law
Chile Minister of Economy Juan Andrés Fontaine met yesterday with representatives of industrial fishing workers and artisanal purse seine fishermen from the whole country. Both sectors, which represe...
Dongwon launches new tuna fishing vessel 'Jubilee'
South Korea Dongwon Industries, the country's largest deep-sea fishing company, has launched today its latest purse seiner, Jubilee, to modernize its increasingly aging fleet. The 2,200-ton vessel, launched to c...
 
Maruha Nichiro Corporation
Nichirei Corporation - Headquarters
Pesquera El Golfo S.A.
Ventisqueros - Productos del Mar Ventisqueros S.A
Wärtsilä Corporation -Wartsila Group Headquarter-
ITOCHU Corporation -Headquarter-
BAADER - Nordischer Maschinenbau Rud. Baader GmbH+Co.KG (Head Office)
Inmarsat plc - Global Headquarters
Marks & Spencer
Tesco PLC (Supermarket) - Headquarters
Sea Harvest Corporation (PTY) Ltd. - Group Headquarters
I&J - Irvin & Johnson Holding Company (Pty) Ltd.
Blue Continent Products (Pty) Ltd - (Oceana Group Limited)
AquaChile S.A. - Group Headquarters
Pesquera San Jose S.A.
Nutreco N.V. - Head Office
CNFC China National Fisheries Corporation - Group Headquarters
W. van der Zwan & Zn. B.V.
SMMI - Sunderland Marine Mutual Insurance Co., Ltd. - Headquarters
Icicle Seafoods, Inc
Starkist Seafood Co. - Headquearters
Trident Seafoods Corp.
American Seafoods Group LLC - Head Office
Marel - Group Headquarters
SalMar ASA - Group Headquarters
Sajo Industries Co., Ltd
Hansung Enterprise Co.,Ltd.
BIM - Irish Sea Fisheries Board (An Bord Iascaigh Mhara)
CEFAS - Centre for Environment, Fisheries & Aquaculture Science
COPEINCA ASA - Corporacion Pesquera Inca S.A.C.
Chun Cheng Fishery Enterprise Pte Ltd.
VASEP - Vietnam Association of Seafood Exporters & Producers
Gomes da Costa
Furuno Electric Co., Ltd. (Headquarters)
NISSUI - Nippon Suisan Kaisha, Ltd. - Group Headquarters
FAO - Food and Agriculture Organization - Fisheries and Aquaculture Department (Headquarter)
Hagoromo Foods Co., Ltd.
Koden Electronics Co., Ltd. (Headquarters)
A.P. Møller - Maersk A/S - Headquarters
BVQI - Bureau Veritas Quality International (Head Office)
UPS - United Parcel Service, Inc. - Headquarters
Hamburg Süd Group - (Headquearters)
Armadora Pereira S.A. - Group Headquarters
NOAA - National Oceanic and Atmospheric Administration (Headquarters)
Omega Protein Corporation
Marona S.A.
Mowi ASA (formerly Marine Harvest ASA) - Headquarters
Marubeni Europe Plc -UK-
Findus Ltd
Icom Inc. (Headquarter)
WWF Centroamerica
Oceana Group Limited
The David and Lucile Packard Foundation
Ajinomoto Co., Inc. - Headquarters
Friosur S.A. - Headquarters
Cargill, Incorporated - Global Headquarters
Benihana Inc.
Leardini Pescados Ltda
Mitsubishi Corporation Marine Products Depts. D.Team
CJ Corporation  - Group Headquarters
Greenpeace International - The Netherlands | Headquarters
David Suzuki Foundation
Fisheries and Oceans Canada -Communications Branch-
Mitsui & Co.,Ltd - Headquarters
NOREBO Group (former Ocean Trawlers Group)
Natori Co., Ltd.
Carrefour Supermarket - Headquarters
FedEx Corporation - Headquarters
AKBM - Aker BioMarine ASA
Seafood Choices Alliance -Headquarter-
Austevoll Seafood ASA
Walmart / Wal-Mart Stores, Inc. (Supermarket) -Headquarter-
New Japan Radio Co.Ltd (JRC) -Head Office-
Gulfstream JSC
INVE Group - Head Office
Marine Stewardship Council - MSC Worldwide Headquarters
Royal Dutch Shell plc (Headquarter)
Genki Sushi Co.,Ltd -Headquarter-
Iceland Pelagic ehf
AXA Assistance Argentina S.A.
Caterpillar Inc. - Headquarters
Tiger Brands Limited
Morpol ASA - Group Headquarters
SeaChoice
National Geographic Society
AmazonFresh, LLC - AmazonFresh

Copyright 1995 - 2019 Fish Info & Services Co.Ltd| All Rights Reserved.   DISCLAIMER