Abstract
The Hannibal Bank sits within the Coiba UNESCO World Heritage Site in Pacific Panama and is also a fisheries management zone. Despite the protected status of the area and the importance of the Bank for commercial fish species such as snapper and tuna, the seamount has received no detailed survey except some collection of organisms. This study mapped the major topographic features and complexity of the Hannibal Bank seamount using acoustic remote sensing. A survey area of around 125 km2 was defined using existing charts and side-scan sonar data were collected during July 2008. A bathymetric output was imported to ArcGIS where a digital bathymetric model and slope map were created. The Benthic Terrain Modeler (BTM) extension for ArcGIS was used to calculate bathymetric position index and rugosity, and used to create a map of zones representing the various seabed morphology zones. The Hannibal bank is an elongated, triangular guyot (flat topped seamount), which ranges in depth from 53m to 416m, covers an area of 76 km2 and is 14.4 km long and 7.1 km wide. Hannibal bank is composed of steep slopes, more gentle slopes, top of the seamount, crests (elevated ridges at the top of the pinnacles), rugose areas (on crests, top of seamount and slope), gullies and pinnacles. The bank is asymmetric in nature with the Northerly side having a relatively gentle slope with gullies across the surface compared to the SouthWest side which is far steeper and more rugose. There are two pinnacles to the North and South East of the bank that range in depth from 180 to 333 m. Rocky substrate makes up 22.6 km2 of the bank and sediment 37.8 km2. The bank and its steeply sided, rugose areas and pinnacles provide upright structures which can disrupt and topographically enhance currents, increasing productivity. The rugose areas of Hannibal Bank should be primary targets for further research efforts as they may contain corals and their rugosity indicates that these should be some of the highest faunal diversity areas of the bank. Hannibal Bank is likely to come increasing pressure in the future through climate change and fishing and this study has produced valuable information to assist in the future mapping and management of habitats, associated species and fisheries.
Highlights
Seamounts are found in oceans worldwide and are primarily composed of basalt but their exact form depends on water depth, chemistry of the magma source, age of the seafloor, and the origin of the magma intrusion in to the water column (Wessel, 2007)
The work described in this study provides the first steps in research on seamounts for this region and assists the global research effort to improve our understanding of seamounts
This study provided the first detailed bathymetric study of the Hannibal Bank and identified seven main zones, which include rugose, probably rocky areas of higher complexity that are worthy of further investigation
Summary
Seamounts are found in oceans worldwide and are primarily composed of basalt but their exact form depends on water depth, chemistry of the magma source, age of the seafloor, and the origin of the magma intrusion in to the water column (spreading zone, mid plate hotspot or subduction zones) (Wessel, 2007). The physical presence of seamounts modifies local hydrographic conditions by interacting with deep water currents creating areas of upwelling This process brings cooler nutrient rich water from deeper areas towards the surface and the photosynthetic zone, producing an area of high primary and secondary productivity around the seamount compared to the surrounding area (Boehlert & Genin, 1987; Genin, Haury& Greenblatt, 1988; Rogers, 1994; Koslow, 1997; Koslow, GowlettHolmes, Lowry, O’Hara, Poore & Williams, 2001; White, Bashmachnikov, Arístegui & Martins, 2007). The CNP and its Marine Protected Special Zone (Hannibal Bank) is a UNESO World Heritage site because of their key ecological link in the Tropical Eastern Pacific (ANAM, 2009) It is a 1 781km fisheries management zone within the World Heritage and is one of the most important fishery areas for species such as grouppers and snappers in the Gulf of Chiriqui (Vega, Robles & Cipriani, 2011). The work described in this study provides the first steps in research on seamounts for this region and assists the global research effort to improve our understanding of seamounts
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
