---

This page is intended to highlight some of the most evident issue of marine environmental degradation in Dominica. Those that want to get involved in reversing some of the negative trends, will hopefully find inspiration from this summary.

Status of Marine Habitats in 2007:

Human activity along Dominica's shores can be traced back several thousand years, but the heaviest uses are likely to have started in the mid 1700s with the first concerted settlement attempts by the French and British. See the writings by Dr. Lennox Honychurch for further historical information at www.lennoxhonychurch.com

The steep terrain of this young volcanic island (with its recent volcanic formations occurring less than 1.8 million years ago) is evident in its narrow shelf area and rugged interior. Settlements have historically sought the coastal zones and in particular the valleys opening to the sea. Valleys offer the best arable land, easy access to inland areas and water which became an important source of energy for the mills of Dominica's estates. This scenario has put marine life and habitats in close proximity with population centers. Herein lie the main sources of marine environmental degradation.

Sediment runoff from land, a natural process, is exacerbated by activities such as deforestation for agriculture, logging and other activities and purposes. In essence, any activity that decreases the sediment retention (for example via vegetation) of a particular area leads to increased terrestrial runoff. Increased sedimentation due to infrastructural development and sand/gravel quarrying are among the recent sources of this type of disturbance. The negative impacts of this process include the suffocation of marine organisms, weakening of animals allocating excessive energy to rid themselves of sediment, and decreased light levels affecting photosynthetic organisms. The consequences can bee seen in the burial and consequent death of coral assemblages (Fond Cole) and sea grass habitats (West Coast).

But coastal zone degradation comes in many forms. The most evident is the illegal and legal dumping of building materials, as well as industrial and household refuse. Unfortunately, evidence of this activity is commonly seen throughout the island. Once submerged in the sea, these materials are out of sight and out of mind for some, but strong storms and hurricanes occasionally spit these materials back onto allowing for reconsideration of this practice.

When humans add materials into the sea, and the concentration of these "additions" exceeds the natural background levels, we speak of contamination. When contamination leads to the degradation of marine habitats and or human health, as well as human interests in marine resources, pollution is the term used by international conventions. Measurements of marine pollution in Dominica have not been carried out to date. Signs of contamination, however, are evident in the vicinity of population centers. The clearest signs come in the form of household and industrial waste and debris, which physically damages habitats and sessile organisms, and increased algal cover.

Other forms of degradation arise from the extraction or harvesting of marine life. Both the extraction techniques applied and the biomass removed can lead to the collapse of individual species or lead to phase shifts within entire ecosystems. The narrow sublittoral zone of Dominica represents a limited resource. Therefore, the multitude of fishing techniques (line and hook, fish pots, seine nets, and spear fishing) used for the past centuries have depleted reef fish communities in Dominica to a point many species are rarely seen and large reef / near-shore demersal pelagic fishes are an uncommon sight. Slow growing coral reefs are being out-competed by fast-growing algae as there are not enough grazers to keep the algae in-check. Similarly, larvae of sessile organisms find little new space (generated by gazing) to settle and the live cover of reef corals in Dominica is steadily decreasing as a result of the aforementioned disturbances and the emergence of more frequent regional disturbances.

Although no longer practiced today, mining of stony corals for the production of lime necessary in construction prior to the availability of cement, was common practice from the 1770s up into the mid 1900s. It is unclear how much habitat was lost this way, but it is a form of degradation that preceded what we are doing to coral reefs today.

Regional disturbances include the rise of sea surface temperatures linked to global warming. These events have increased in frequency and intensity in recent decades. In 2005, elevated sea surface temperatures led to the severest bleaching episode ever recorded for the Caribbean. It was centered in the NE Caribbean, and Dominica was one of the islands whose coral reefs suffered the most. The loss of live coral cover and the virtual absence of particular species were the result of this event (that followed closely on the heels of the bleaching events of 2003 and 2004). These disturbances lead to the weakening of species and ecosystems, which, alone, may not kill a species or habitat, but when combined with multiple other local disturbances, individual species or habitats have already. The recent increase in coral diseases may be linked to such conditions: where corals weakened by local and global stressors become more susceptible to killer pathogens.

Regional disturbances are not easily mitigated by small island nations and this highlights the urgency of immediate action in reducing local disturbances if the island's coral reef resources are to have a chance of being conserved.

Invasive species can pose problems in several ways. They can out-compete local species, possibly taking over entire habitats, and they may carry other organisms like bacteria with them that could affect local species. The ballast water from boats and ships is one common means of invasion by such species. Airborne sources (Sahara Dust) of introductions have also been documented in a collaboration (2002) with R. Armstrong (U Puerto Rico).

The stony coral Tuastraea coccinea is invasive and currently can be found in the Scott's Head Soufrier Marine Reserve. Its ditribution is beeing monitored by S. Steiner. It is not a reefbuilding species and tends to remain in small patches. To date, these patches are spread of a few 100 m2.

Of much greater concern, is the widespread presence of the invasive seagrass Halophila stipulacea documented by D. Willette. This is an aggressive species that can out-compete the local seagrass species. It seems that Prince Rupert's Bay may be the area where this species was introduced, and has been recorded along most of the west coast between Fond Cole and Lamothe Bay.

SCCS1107