Southeastern US Marine Ecosystems and Hydrocarbon Exploration

SOUTHEASTERN US MARINE SOUTHEASTERN US MARINE ECOSYSTEMS AND ECOSYSTEMS AND

HYDROCARBON EXPLORATIONHYDROCARBON EXPLORATION

Steve W. Steve W. Ross Ross

SEUS Marine SEUS Marine EcosystemsEcosystems

• Large estuaries and numerous rivers• Long coastlines, inshore and offshore• Extremely high marine and estuarine biodiversity (> 1000 spp. of fishes < 200 m, more than anywhere else in US except FL)

Moderate climateTemperate latitudes (warm and cool temperate with

subtropical inputHabitat diversity high (shallow and deep)Gulf Stream (nutrient dynamics, temperature modulation, transport)

Manteo ProspectHatteras Middle Slope

(“The Point”)

Since the late 1980s to early 1990s, there has been substantial progress in understanding offshore ecology.Even so, the farther offshore we go, the less we know, and in some cases there are almost complete knowledge gaps.

500 m

1000 m

• Dynamic oceanography• Rugged terrain• High carbon deposition• High infaunal biomass• Unusual communities• High productivity and biological activity

Depths in meters

Muds and canyons north of Cape Hatteras

Hard grounds and carbonate sands south of Cape Hatteras

A virtual data desert beyond 2000 m, esp. for benthic ecology & biology

Gulf Stream dominates regional oceanography.

Influences:•Weather/climate•zoogeography•genetic connectivity•nutrient delivery to shelf via upwelling•Designated as EFH

Sargassso Sea

Spawning migration

Juvenile recruitmentEstuarine-dependent species:Atlantic croakerAtlantic menhadenGulf flounderSpotSilver perch

Spring

FallWinter

Summer

Juvenile recruitment

Spawning migrationAnadromous species:American shadBlueback herring Hickory shadStriped bassAtlantic sturgeon

Catadromous species: American eelSpawning migration

Juvenile recruitment

Reef-associated species:Snapper/grouper

Juvenile recruitment

Freshwater Estuaries Nearshore Offshore

Michel 2011

Great connectivity between river/estuarine and offshore systemsBut less connectivity with deeper (> 200 m) waters

Takes place generally inshore

of 200 m

Big issues facing these resources are

degraded habitat and overfishing (by

catch issues).

Demersal fishes

Cat

ch (

mil

lion

ton

nes

)

0

2000

4000

6000

8000

10000

12000Pelagic fishes

0

8000

16000

24000

32000

40000

48000

0

500

1000

Reef associated fishes and flatfishes

Year

19501955

19601965

19701975

19801985

19901995

20002005

0

1000

2000

3000

4000

5000

6000

Flatfishes

All fishes

19501955

19601965

19701975

19801985

19901995

20002005

0

15000

30000

45000

60000

75000

90000

105000

120000

135000

Regional commercial fish landings. The great majority of these are caught in shelf depths. There are few current fisheries deeper than 200 m (exceptions = wreckfish, offshore pelagics)

(Michele 2011, www.seaaroundus.org)

This example of detailed estuarine and nearshore habitat mapping is typical of many states. This level of detail or precision is very rare offshore. Ecological knowledge declines rapidly with increasing distance offshore.

after Deaton et al. 2010

SEAMAP-SA 2001

South Atlantic BightMarine Assessment

Benthic Habitat Hardbottom

Anderson et al. (in review 2015)

Shelf (<200 m) Hardbottom•Dominant resources = snapper, grouper, porgy complex & other reef fishes•Invertebrate fauna very rich but poorly studied•Reefs support diverse subtropical communities•Designated as EFH•Overfishing & habitat degradation are issues. Do the 6 shelf edge MPAs offer sufficient protection?

Sedberry et al. (2006)

Blackbelly rosefish

Snowy grouper

Most data < 200 m)

Deep-sea (> 300m) Coral Habitats• Banks scattered, but common on SEUS slope (370-

800 m), also on rocks and in canyons

• Very rugged topography (30-100 m tall mounds)

• High species richness, high numbers of species new to science and new to region

• Provide shelter, feeding areas, and possibly spawning areas to many species

• Support commercial & potentially commercial spp.

• Influenced by Gulf Stream dynamics, large environmental variations

Environmental data (2 Dec 09 – 16 May 10) from lander deployed at deep coral mounds off Cape Lookout, NC (430 m).

Note Gulf Stream intrusions on bottom (Temp & other spikes).

Gulf of Mexico 425 m

Gulf Stream

Loop Current

More deep-sea heterogeneity than expected

Deep Reef & Canyon Study Areas (groupings based on fish communities)

Genetic discontinuity also displayed by L. pertusa deep corals: GOM differs from SEUS

South Atlantic Fishery Management Council created 4 deep coral HAPCs (23,000 sq. miles) that protect most deep coral habitat off the SEUS.

The largest protected area off the continental US.

Off Cape Hatteras

Pelagic to Mesopelagic Environment:•Important fisheries (billfishes, sharks, dolphin, mackerels, tunas)•Highly migratory species•Charismatic & endangered species (mammals, turtles, seabirds, whale sharks)•Mesopelagic may have greatest abundance & biomass of any marine habitat•Role of mesopelagic fauna in carbon movement probably far underestimated•Important conduit for larval movement•Surface to mid-depth is area of likely spill impacts (as in DWH)•Important nursery and feeding habitats (Sargassum)

At least 80 fish species use Sargassum(Casazza & Ross 2008)

NE FACING SLOPE TOP WEST FACING SLOPE

¯ ¯

Cape Fear coral mound 3-D view

Cape Fear Bank

Baltimore Canyon

Areas recently (2006- ) mapped with high

detail, high precision multibeam sonar

Mapped boxes are only 4.4% of the two

planning areas.

RESEARCH TO RESEARCH TO CONSIDERCONSIDER

• Severe lack of biological data > 200 m (benthic & mesopelagic)Severe lack of biological data > 200 m (benthic & mesopelagic)• Multibeam mapping of interest/target areasMultibeam mapping of interest/target areas

– Strong need for better habitat descriptionsStrong need for better habitat descriptions• Trophodynamic studies (most bang per $$)Trophodynamic studies (most bang per $$)

– Complete unfinished studies, add othersComplete unfinished studies, add others• Interaction of physical oceanography and biologyInteraction of physical oceanography and biology

– larval transport, genetic continuity, dispersal barriers or larval transport, genetic continuity, dispersal barriers or conduitsconduits

• Population structure & connectivity studiesPopulation structure & connectivity studies• Marine larvae dynamicsMarine larvae dynamics

– distributions, seasonality, movementsdistributions, seasonality, movements• Locate ocean spawning areas for important speciesLocate ocean spawning areas for important species