Groupers’ plight spells trouble for ecology and blue economy
There are six kinds of grouper: monkey rockfish, finescale rockfish, Nassau grouper, misty grouper, yellowfin rockfish and black grouper.
These six grouper species used to be on the menu and for sale across Bermuda. However, now we have only one large grouper in large quantity: the black grouper.
If you are lucky or well-connected, you might be able to get monkey rockfish, but gone are the days where anyone could catch a decent-sized Nassau grouper from the shore, or be sure to pull up a monkey rockfish from the side of the Banks. Large grouper used to represent a fishery of more than 100,000kg per year back in the mid-1970s. Caught biomass crashed to less than 10,000kg per year in the mid-1990s, primarily because the fish were gone, but to a small degree also fish pots were banned and new ways to catch large grouper had yet to be developed.
Black grouper catch has been increasing in the past 20 years, with take at around 22,000kg per year in 2015, as people figured out how to troll for them.
However, black grouper catch experienced a rapid decline in 2016 and 2017 — to 16,000kg in 2017. A drop from 22,000kg to 16,000kg represents a very highly significant decline.
Monkey (also known as salmon) rockfish used to represent 25 per cent of the catch in the 1990s, but has declined to less than 4 per cent of annual catch. Misty grouper are also still not a protected species, but their yield has declined from 10 per cent of catch down to less than 1 per cent of catch by 2000, where it remains still.
Caught biomass does not represent the number of fish still remaining in Bermuda waters. Catch and release of tagged fish, or in-water surveys using standardised methods, are required to determine how many fish are actually available to catch and whether our fish stocks remain at sustainable levels.
In 2004, I started the Bermuda Reef Ecosystem Assessment and Mapping Programme. My team of Bermudian and overseas research scientists and technicians mapped all 35,000 patch reefs and 400 sq km of forereef of Bermuda to a Geographic Information System. We subsequently assessed the state of coral reefs and associated fishes across 178 sites during 2004 to 2011. Since then we reassessed 40 sites across the reef platform for reef and fish condition, using the Global Coral Reef Monitoring Network’s Caribbean procedures, which we helped develop in 2014.
We counted fish at each reef along replicate 30-metre transects using internationally standardised techniques to get statistically powerful data on fish abundance and size for over 100 species of fish, including the large grouper species. Our baseline surveys from 2004 to 2011, and our two additional monitoring surveys in 2015 and 2016, each independently determined the same result for large grouper.
These reports can be seen at our website at Bermuda BREAM.org
Based on internationally accepted standards, Bermuda reefs near the shore, in the lagoon, along the shallow rim reef that surrounds the lagoon and island, and at 30ft depth, 60ft depth and 90ft depth were all critically depleted of large grouper. The loss of grouper is system-wide.
Based on the severity of the loss of large grouper species across Bermuda’s reefs, we made the following recommendations, which we still stand behind a year later:
Recommendations for action
The restoration of grouper and snapper stocks and enhanced protection along with improved management to prevent future declines should be a national priority.
Support the monitoring of coral reefs and fishes
The Bermuda Government has committed to the protection and management of Bermuda’s coral reefs and marine resources through the creation of policy and via its commitments to several local and international conventions, including the Bermuda Biodiversity Action Plan, the Convention on Biological Diversity, the Convention of Migratory Species, and the Convention of Wetlands of International Importance.
However, no government funding for the concurrent monitoring of fish, nor coral reefs is available. Future monitoring of the status and condition of fishes and coral reefs should be supported and funded, at least to some extent, by the Bermuda Government.
Support the development of an environmental decision-making protocol
Our Bermuda Bream monitoring programme assessed a suite of factors that indicated the condition of fishes or coral reefs in a statistically rigorous and mathematical manner.
Changes in each factor should function as indicators of change that are directly linked to specific management and conservation actions.
It would be preferable that Government and non-Government stakeholders assisted in the development of an Environmental Decision-Making Protocol that defined what actions were available and appropriate responses to changes in the abundance or distribution or status of each of the critical reef health indicators we assess in this report.
The development of an EDMP would accelerate the rate at which resource managers and conservationist could respond to problematic changes in the condition of our reefs or fish stocks, and would provide nationally accepted goals for marine environmental health and resilience.
Restoration of predatory fish Populations
1, Enhance the stocks of groupers by introducing a limited ban on the capture and sale of black groupers during their spawning period (as we currently do with spiny lobster), based on evidence of the timing of their maximum aggregation at spawning sites.
2, Consider bag and size limits on grey snappers, schoolmaster snappers, yellowtail snappers, graysbys and coneys (all of which are also depleted).
3, Expand our knowledge of juvenile predatory fish habitats, which are generally within the lagoon (patch reefs), along the shore (nearshore), and within enclosed bays (inshore). Many species of offshore reef fish, including predatory fish species, start life by settling as juvenile fish to coastal habitats, only to move offshore as they mature.
4, Reduce coastal development and pollution impacts to the marine environment, as many juvenile reef fishes are found the inshore and nearshore waters first before they move to outer reef areas.
5, Design coastal structures such as docks and breakwaters with rough surfaces or attachments so that they provide additional habitat for juvenile and adult fishes.
Expand marine spatial protected areas
Protected areas act as marine resource “banks” and provide “interest” in the form of continuously available fishes for commercial and recreational harvest, through the spillover effect, and enhanced reproductive output.
We recommend the expansion in the distribution of protected areas that span the reef platform from inshore bays, along lagoonal chains of reefs, out to the forereef. These areas are juvenile habitats that are currently threatened due to a lack of smaller predatory fishes and high damselfish densities. Networks of protected reefs allow fish to transition from zone to zone throughout their life cycle.
Expand the fishing licence programme
Recently the fishing licence programme was expanded to include recreational spearfishers. We recommend that all recreational fishers require a licence. This would include both those fishing from the shore and those using marine craft. Access to fishing activity should not be financially onerous to those with low income, however. No-cost licences to locals who use hand lines within their parish of residence could be provided so that the financially challenged retain access to fishing activities.
Bermuda relies on resilient and sustainable grouper fisheries to provide jobs, food security and to enhance our tourism product. Additionally, those groupers provide critical ecological functions that sustain our coral reefs and associated habitats and industries including the blue economy of marine tourism.
As such, grouper stocks must be maintained at levels that allow the fish to carry out their ecological roles on the reefs as well as provide food stock for our fisheries industry. Bermuda needs these fish to thrive in our local waters, and we in Bermuda need to ensure big groupers remain here.
Thaddeus Murdoch, PhD, is Bermuda Environmental Sustainability Taskforce’s Marine Conservation Team resident scientist