Environmental impacts of oil spills

Marine life and fisheries in the Gulf of Mexico

September 27, 2010, 4:07 am
Source: NOAA
Content Cover Image

Clymene Dolphins. Credit: NOAA

Fish and Shellfish

Overall Economics of Gulf Fisheries

One of the biggest industries in the Gulf of Mexico is the fishing (commercial and recreational).

In 2008, commercial fishermen in the Gulf of Mexico harvested 1.27 billion pounds of finfish and shellfish that earned $659 million in total landings revenue. Two of the largest commercial fishing operations in the Gulf of Mexico are red snapper and shrimp. Brown shrimp is the most important species in the U.S. Gulf fishery, with principal catches made from June through October.

There were 3.2 million recreational fishermen who took a fishing trip in the Gulf of Mexico region, and they took 24 million fishing trips in 2008.

Shrimp Species

Major shrimp species in the Gulf of Mexico include white shrimp, pink shrimp and brown shrimp. These species are mainly located in coastal areas. During the spring, the young, or postlarvae, migrate from coastal areas. Impacts on these shrimp will increase as the oil slick approaches nearshore areas.

Shrimp species will be impacted due to mortality of adults, as well as postlarvae. In particular, brown shrimp postlarvae will be migrating out of inshore waters from February to April, while white shrimp will begin migration in May and continue through November. The spill could have impacts not only on shrimp catches this year, but also next year if postlarvae mortality is high.

caption Credit: DNR The economic impact of the oil spill on shrimp could be extensive. The Gulf region landings of shrimp are the nation’s largest with 188.3 million pounds or 73 percent of the national total. Louisiana led all Gulf states in landings with 89 million pounds with a dockside value of $130.6 million in 2008, followed by Texas (63.8 million pounds, dockside value of $157.2 million), Alabama (17 million pounds, dockside value of $38.4 million), Florida’s West Coast (9.9 million pounds, dockside value of $23.3 million), and Mississippi (8.6 million pounds, dockside value of $17.1 million).

The following shrimp species are found in the Gulf of Mexico:

  • Brown shrimp (Farfantepenaeus aztecus)
  • White shrimp (Litopenaeus setiferus)
  • Pink shrimp (Farfantepenaeus duorarum)
  • Royal red shrimp (Pleoticus robustus)
  • Seabobs (Xiphopenaeus kroveri) - incidental bycatch
  • Rock shrimp (Sicyonia brevirostris) -incidental bycatch


There are three species of crabs in the Gulf of Mexico area: blue crab, Gulf stone crab, and stone crab. Blue crab occurs almost exclusively in state waters with peak spawning occurring in August-September. Eggs and larvae develop and settle in the estuaries until crabs reach harvestable size in April-May. The Gulf stone crab is relatively abundant in the Louisiana, Mississippi and Alabama nearshore areas in the spring period. The stone crab distribution is relatively limited.

Blue crabs are the most economically valuable crab species for the region. Louisiana lands approximately 26 percent of the total blue crabs for the nation or 41.6 million pounds in 2008, with a dockside value of $32 million. Landings and dockside values for the other Gulf states were: West Florida, 2.7 million pounds, $3.3 million, Texas, 2.6 million pounds, $2.3 million, Alabama, 1.8 million pounds, $1.5 million, Mississippi, 450,000 pounds, $447,000.


The Gulf region leads the nation in the production of oysters, some 67 percent of the nation’s total. The following landings and dockside value was produced in 2008 in the Gulf states: Louisiana, 12,778,311 pounds, $38.8 million; Texas, 2,679,207 pounds, $8.83 million; Mississippi, 2,610,349 pounds, $6.87 million; West Florida, 2,501,475 pounds, $5.47 million; Alabama, 72,776 pounds, $243,414.


There is a wide variety of fish species in the Gulf of Mexico. In federal waters, the surface-oriented species will be most impacted by the early stages of the oil spill. As the crude oil sinks, the bottom-oriented fish community may be impacted. The major impacts will be on nearshore species or species that may be currently spawning.

In general, reef fish species in the Gulf of Mexico are associated with bottom topographies on the continental shelf, coral reefs, artificial reefs, rocky hard-bottom substrates. The majority of these species are inshore of the current location of the oil spill. There are potential negative impacts on fish larval stages since several reef fish are currently spawning or will be spawning if the oil spill continues.

Mortality on larvae caused by the oil spill will result in declines in recruitment in future age classes. This will negatively impact the rebuilding plans for these species, as well as short- and potentially long-term economic impacts on commercial and recreational fisheries in the Gulf of Mexico.

caption Grouper. Credit: NOAA Juvenile red snapper are common on mud bottoms in the northern Gulf, particularly off Texas through Alabama. Also, some juvenile snappers (e.g. mutton, gray, red, dog, lane, and yellowtail snappers) and groupers (e.g. goliath grouper, red, gag, and yellowfin groupers) have been documented in inshore seagrass beds, mangrove estuaries, lagoons, and larger bay systems. As long as the oil spill remains on the surface and offshore, the impacts to reef fish habitat should be minor. However, if the oil slick reaches the bottom or nearshore/inshore areas, the majority of the 42 reef fish species managed in the Gulf of Mexico will be affected.

The commercial landings and dockside value of red snapper, one of the more valuable finfish species, by state for 2008 was as follows: Texas, 869,966 pounds, $2.74 million; West Florida, 847,884 pounds, $2.94 million; Louisiana, 589,379 pounds, $2.03 million; Alabama, 60,391 pounds, $237,141. There were no data available for Mississippi.

Postlarvae and juveniles of menhaden and mullets (winter spawners whose juveniles are now entering the estuaries) may be affected by the oil spill. Depending on current Loop Current dynamics, Atlantic bluefin tuna may also be impacted by the oil spill. Atlantic bluefin tuna larvae may also be present in the region of the oil slick. Their presence however is quite dependent on and related to the Loop Current eddies and fronts. The other consideration is the number and extent of Sargassum mats that may intersect with the oil. The Sargassum is nursery habitat for gray triggerfish and the amberjacks.

There are many groundfish species that are located in the area of the oil spill and associated coastal areas.


caption Blacktip shark. Credit: Alabama Department of Conservation and Natural Resources Shark species are distributed throughout the Gulf region with the highest abundances in the central Gulf from Louisiana to Alabama. Blacktip sharks are particularly abundant in this region and are one of the most commercially important shark species in the Gulf.

During spring and summer months several shark species of management concern use coastal nursery areas, and those areas can be expected to be impacted. In particular, blacktip sharks, spinner sharks, Atlantic sharpnose sharks, and bull sharks are regularly captured during coastal gill net surveys and bottom longline surveys.

Adult blacktip sharks are more abundant in the central Gulf of Mexico than any other region; second only to sandbar sharks (also widely distributed in the central Gulf) in commercial importance. Tiger sharks are not reported to utilize coastal nursery areas, however, their young are distributed offshore. Whale sharks are distributed along much of the Gulf of Mexico with highest concentrations off the Louisiana Delta; their distribution can be both near coastal and well offshore.

Fish Species in Federal Waters

Sharks (Surface-Oriented)

  • Whale sharks
  • Hammerhead sharks
  • Tiger sharks
  • Silky sharks
  • Mako sharks

Rays (Surface-Oriented)

  • Manta rays
  • Eagle rays
  • Cownose rays

Finfish (Surface-Oriented)

  • Tunas
  • Billfish
  • Molas

Sharks and Finfish (Bottom-Oriented)

  • Sharks, small coastal and large coastal management species
  • Groupers
    • Rock Hind
    • Yellowfin
    • Scamp caption Manta ray. Credit: NOAA
    • Red Hind
    • Goliath
    • Nassau
    • Red
    • Gag
    • Yellowedge
    • Snowy
  • Snappers
    • Mutton
    • Blackfin
    • Red
    • Gray
    • Lane
    • Silk
    • Yellowtail
    • Vermillion
  • Tilefish
    • Blackline
    • Anchor
    • Blueline
    • Golden
    • Goldface
  • Gray Triggerfish and Jack
  • Greater and Lesser Amberjack

Fish Species in State Waters

Common Sharks

  • Bull shark
  • Blacktip shark
  • Spinner shark
  • Silky shark
  • Atlantic sharpnose shark

Common Finfish

  • Red snapper
  • Mullet
  • Lane snapper
  • Red drum
  • Gray snapper
  • Vermillion snapper
  • King and Spanish mackerel
  • Gag grouper
  • Spotted seatrout
  • Cobia
  • Greater amberjack

Marine Mammals

There are two resident species of large whales in the Gulf of Mexico that may occur in the area of the spill: Bryde's whales and Sperm whales (endangered).

caption Two sperm whales "fluke-up" near the Texas A&M Research Vessel Gyre. Credit: BOEMRE Bryde’s whales (pronounced Brew-duhs) are not listed as endangered or threatened, but they are protected under the Marine Mammal Protection Act. Bryde’s whales are baleen whales, meaning they have hair-like “teeth” in their mouths that the whales use to filter water and trap their food. A small population of Bryde’s whale (Balaenoptera edeni), the only baleen whale to commonly occur in the Gulf, inhabits the shelf break region in the northeastern Gulf. Sperm whales are much more abundant than Bryde’s whales and are found throughout the northern Gulf of Mexico, especially near the 1,000 m depth contour.

Sperm whales are listed as Endangered under the Endangered Species Act, and are also protected under the Marine Mammal Protection Act. Sperm whales are the largest toothed whales, and they hunt relatively large-bodied prey in deep water.

The greatest threat to whales from the oil spill is probably fouling of the baleen. If Bryde's whales are skim-feeding in the slick or otherwise get oil in their mouths, the oil would quickly clog and foul the baleen. Fouled baleen could lead to compromised feeding, starvation and death.

Skin contact or inhalation exposure is probably a much less serious risk for large whales, and would probably only have sub-lethal effects. Long-term impacts also are possible through take-up of oil components through the food chain and likely “biomagnification” of the contaminants in large marine mammals.

US Marine Mammal Protection Act

The following 21 marine mammals that routinely inhabit the northern Gulf are protected under the U.S. Marine Mammal Protection Act:

  1. Bottlenose dolphin
  2. Atlantic spotted dolphin
  3. Bryde’s whale caption Rough-toothed dolphin in the northern Gulf of Mexico. Credit: BOEMRE
  4. Sperm whale (also protected by the Endangered Species Act)
  5. Dwarf sperm whale
  6. Pygmy sperm whale
  7. Cuvier’s beaked whale
  8. Blainville’s beaked whale
  9. Gervais’ beaked whale
  10. Short-finned pilot whale
  11. Killer whale
  12. False killer whale
  13. Pygmy killer whale
  14. Melon-headed whale
  15. Risso’s dolphin
  16. Rough-toothed dolphin
  17. Fraser’s dolphin
  18. Pantropical spotted dolphin
  19. Striped dolphin
  20. Clymene dolphin
  21. Spinner dolphin

Sea Turtles

caption Kemp's Ridley. Credit: FWS

There are five species of turtles that inhabit the Gulf of Mexico:

  • Kemp’s Ridley (Lepidochelys kempii) (endangered)
  • Leatherback (Dermochelys coriacea) (endangered)
  • Loggerhead (Caretta caretta) (threatened)
  • Green (Chelonia mydas) (endangered)
  • Hawksbill (Eretmochelys imbricata) (threatened)
  • Possible — olive ridley (Lepidochelys olivacea) (threatened)

The only place in the world that the Kemp’s Ridley nests is in the western Gulf of Mexico. They are now in the peak of their nesting season. One of the only foraging grounds for the Kemp’s Ridley is in the area of the oil spill. They are currently foraging there.



(2010). Marine life and fisheries in the Gulf of Mexico. Retrieved from http://www.eoearth.org/view/article/51cbefaf7896bb431f69e96c


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