Biodiversity within Güllük gulf, threats due to high levels of nutrients (eutrophication), and pollution; measures to be taken to protect and preserve:
Current Situation:
Slightly North of Gökova Gulf, Güllük Gulf, much like its neighbor is rich in biodiversity throughout, and within its two inner gulfs of Mandalya and Asin.
The entire marine basin is home to endangered species, both endemic and migratory and which are under protection by several international conventions. Güllük Gulf consists of several different habitats (fishing weir, wetland, lagoon, etc)
Although the marine habitat with its numerous small coves has been greatly disturbed during the past 15 years due to uncontrolled, environmentally devastating aquaculture practices, biodiversity in sea and on land has somehow persevered.
In recent years complaints on the nature of aquaculture practices have led the Ministry of Environment to issue a notification (2007, Denizlerde Balık Çiftliklerinin Kurulamayacağı Hassas Alan Niteliğindeki Kapalı Koy ve Körfez Alanlarının Belirlenmesine İlişkin Tebliğ (resmi Gazete #26413, 24.01.2007) which sets a number of baseline parameters for sensitive gulfs where aquaculture practices can be undertaken such as minimum depth for the cages to be set (30 meters), minimum current speed (0,1 meters/second) and minimum distance to land (0,6 nautical miles). One other parameter which the notification mentions is eutrophication, where gulfs with a number 4 on the TRIX index is considered "cultivatable", any number between 4 and 6 posing a risk towards euthrophication, any number above 6 depicting a eutrophic marine area, where such practices should be stopped.
As can be easily understood by the low parameters for depth, speed of current, as well as distance to land, the negative impacts of aquaculture practices on sensitive ecosystems would be quick to show themselves, as we now see in Güllük Gulf. More specifically throughout the Asin Gulf, which is by nature a shallow basin resting on the coastal shelf, with a complicated current stream, (TUBITAK-METU report: Muğla Kıyılarında Koyları Etkilemeyecek Deniz Balığı Yetiştirme Alanlarının Tespiti, TUBITAK-ODTÜ, September 2005, pages 132-133, 162-163) the risk of eutrophication already present in its coves have spread throughout the inner gulf as the cages were set right in its center where the deepest point, a thorough, meets the depth requirement of 33 meters. The center of the inner gulf with its deepest point set at 37 meters in a single spot, the rest of the sea floor higher at around 27 meters and less, makes the area risky for any practice which has the potential to increase euthrophication, namely aquaculture practices. However due to its geological structure, the temperature of the sea water is warmer in Asin than in other areas throughout Güllük Gulf, which allows coraline formations to appear throughout the inner gulf, and which also makes this delicate natural habitat a prime spot for the fish farms as growth is faster in protected warm waters.
Güllük Gulf is typical of most Aegean-Mediterranean coastline, with sharp inclines of rocky formations ending in the sea. Thus the thorn-bushes, and other plants endemic to these rocky shores become extremely important in preventing erosion during the rainy months in Spring and Fall, where precipitation can be extreme, causing flooding around riverbeds. Floods which occur around the gulf at times saturate the gulf with sediment rich in organic matter, seeds, and other nutrients, contributing to the eutrophic nature of the inner gulfs. In current years, construction projects around the gulf area has dislocated many important plant areas, replacing them with cement structures and asphalt roads. Any adverse change in the natural landscape promotes erosion.
Under such circumstances, whereas a gulf such as Gulluk hosting many endangered species should be protected by a special status by the Ministry of Environment, is instead put in cross fire between rampant urbanization and the aquaculture practices. Although Gulluk Gulf is obviously a wrong choice for culture fish farming, in its current state excess feed and feces from the large populations of seabass and seabream pumping excess nutrients to an already overloaded, eutrophic marine environment causes an irreversable destruction on the sensitive sessile species such as corals and Posidonia Ocenica beds in the gulf. The quality of the sea water is badly effected, visibility due to turbidity falling under 1 meter in places, blocking sunlight and thus limiting photosynthesis. Dropping oxygen levels both from desertification on the sea floor and their use to break up the excess waste is ending life in depths where the sun light can no longer reach. A desired effect maybe, for the corporations investing in the gulf as an aquaculture strong spot, as with the destruction of the endangered species, an immediate protection status for the gulf will not be granted.
The Posidonia Ocenica, rightfully named "lungs of the Mediterranean", is under protection by the Barcelona Convention of 1995, to which Turkey is signatory. The fact that the species' livelihood is directly and adversely affected by the drift from the cages that are set up in dangerous proximity to the underwater meadows, has also been widely documented by the METU scientific study of 2003 (pg.101,104-105, 133-134). The adverse results are also in plain view today. In an era in which we are battling with the adverse outcomes of global warming (i.e. desertification) to stand idly by and watch the disappearance of at least two endangered and sensitive species with the ability of photosynthesis, due to procedural errors of human intervention, when the needs and necessities are juxtaposed is hardly acceptable. International organizations such as the NOAA, WRI and IUCN have also confirmed the destruction of the coraline species and the Posidonia meadows, through extensive sharing and exchange of information from the site in question. These organizations have also called for urgent precautions to be taken to stop further destruction of the meadows, all suggestions unfortunately falling to deaf ears both on the production and on the protection side.
The words of Dr. Steve Gittings, a coral expert at the National Oceanic and Atmospheric Association are especially worthy of note:
"Reversing the problem requires aggressive measures that result in improvements in water quality. Moving the aquaculture facilities is probably one requirement. They should not be close to the coral habitat and should not be upstream. When deciding where to locate them, current patterns need to be considered, as you suggest, and they should be in an area that does not take the waste stream toward the coral communities."
In line with the METU report (pg. 162-163), the corals are under direct threat of the deposits from the aquaculture cages, as the current regime in Asin Gulf is mainly from the Northwest to the East, in other words, from the mouth of the gulf towards the shores, carrying all the debris from the cages to the rocky shallow basin on the shore. The corals hanging on the rocks along the coastal shelf are thus directly affected by the excess organic waste and overpopulation of invasive species such as Jania Rubenis, which in turn cling to the corals' prickly surface, suffocating them. Losing their ability for photosynthesis, the corals, some of which have have been formed slowly over half a century, are defenseless to the algae which cover them up, speeding their calcification and gradual death in a matter of weeks.
Dr. Steve Gittings: “Regardless of the cause (for example, aquaculture, inadequately treated sewage, runoff from agricultural facilities, uncontrolled coastal development), nutrients typically promote the growth of leafy and filamentous algae, resulting in the competition for space on reefs. Algae usually wins the battle over corals, which grow very slowly. Algae also allows sediments to accumulate, forming what are sometimes called "algae-sediment mats." The soft surface resulting from this process inhibits coral growth and further accelerates their mortality. Thus corals like the one you photographed, which may take 10-50 years to grow, must compete against algae that can grow in a matter of weeks or months.”
In similar fashion the Posidonia meadows are also adversely affected from the organic overload in the sea water. Dr. Ferit Bingel, the joint-author of the above mentioned METU report details as such: "One of the factors limiting the expansion of Posidonia Ocenica on our shores is the aquaculture practices set up either on, or close to the meadows." He continues to stress the fact that the excess feed and feces from the cages "increase the organic load in the water. In addition the salinity (nutrient) is increased leading to overload (eutrophication) The hanging matter in the water decreases visibility, blocking the essential light for photosynthesis from reaching the meadows. Furthermore, the debris from the cages sink to the sea bottom before having the chance to break down, thus covering the surfaces of the Posidonia shoots, killing them... The meadows, deprived from essential light for photosynthesis, thus shrink in tandem with the increase in organic pollution. It is worthy of note that the space, closest to the production areas, thus emptied as with the death of the sea grass, is in turn taken over by an invasive species: Caulerpa Racemosa." (TUBİTAK-ODTÜ, pg. 101)
As per the above mentioned METU report, Prof. Ferit Bingel and team have recorded the below observation during their extensive analysis of the Güllük Gulf in 2003:
“Within Güllük Gulf where aquaculture practices are densely present, a similar habitat loss has been seen as such around Ziraat Island and Bozburun. Hanging matter density has seriously increased and transparency has starkly diminished while the meadows have been completely obliterated. Where aquaculture farming has recently started around Salih Island, whereas the length of meadow leaves and the density of new shoots are low, the meadow extends to under 20 meters. In this area, Pinna Nobilis, a species under protection, has been encountered in large numbers. Also in Alagün and Kazıklı, both of which have a short history of farming, although the meadows extend to depth below 20 meters, the deterioration in leaf length and the lower density of new shoots, shows us the pressure the meadows are under.” (TUBİTAK-ODTÜ, pg. 104-105)
When Bingel and team's observations of 2004 are compared to the study they conducted the previous year, there is ample proof that the wildlife in the region is under direct threat from organic pollution stemming from aquaculture practices (TUBİTAK-ODTÜ, pg. 105) As of today, we know that the current placement of the cages are either above or very near to Posidonia meadows. And as you can see in the photo below, the meadows areadversely effected from aquaculture prone organic pollution.
During May-June of 2010, new cages are being transferred to new spots within Asin Gulf. Despite all our warnings towards the existing sensitive/endangered species in the region, Muğla Agriculture and Village Works Directorate has declared that the current placements are legal and that there are 80 more such points within the Gulf that have been designated as aquaculture production sites. When all these nodes are covered with cages and full production begins, the current organic pollution in the Gulf will quadruple by best case scenario. When we look at the accelerated destruction of Posidonia meadows within the last year, the enlarged aquatic farmland will seriously hinder the wildlife and biological diversity in the area. As Bingel also mentions in his report, immediately following the new placement of the cages in the middle portion of Asin Gulf, the meadows and Pinna Nobilis have both showed signs of retreating, whereas common species have taken over the places vacated by more sensitive ones. The sensitive species on the other hand have largely disappeared, as they have lost the battle for space and oxygen due to pollution and eutrophication to their stronger counterparts.
Through amateur observation and skin dives, several species, listed in Annex III of the Barcelona Convention, can easily be spotted. These include, but are not limited to: Maja squinado (spider crab), Epinephelus marginatus. Also other species under protection by various international treaties such as the yellow corals, Tonna Galea and Chelonia Mydas (you can see an extensive and incomplete list on the right colum here.)
One of the most important species found in our Gulf is Chelonia mydas. While we think they use the Gulf as a resting and feeding spot during their migration, there is ample proof that the species is being adversely effected from pollution and the massive marine traffic which the aquaculture farms cause in the Gulf. During the few months in which this report was compiled, at least 4 grown samples of this sensitive species has been washed ashore, their shells cracked and the bodies badly decomposed.
The endangered Chelonia mydas, which is currently under protection, can frequently be spotted within Asin and Mandalya inner gulfs in the period of mid-summer to mid-fall. Both the local residents and local fishermen have spotted this seclusive creature. We think the Chelonia mydas uses the area as a feeding spot as the basin is still covered with Posidonia meadows, inhabiting several other species to which the mydas is a natural predator. We have managed to secure the information of both the mydas and the Caretta caretta entry into the Gulf, with help of satellite data provided to us by the kind help of Carribian Conservation Corporation (CCC 1-2) When asked about the possible cause of death of the creatures, CCC staff has told us that the deaths may have occurred due to pollution, getting tangled up in loose fish nets and suffocation. They also mentioned that the fact that the shells have been broken, point to the fact that the animal has been run over by a fast moving marine vehicle post-mortem. Here, Marydele Donnelly provides some extremely useful information:
“The region once supported significant green turtle fisheries but today only 350-400 females nest each year in all of the Mediterranean (females do not nest annually so the entire nesting population is probably three times that size). As the situation has become so precarious for this species, every individual counts."
Other species endemic to the region, such as sandbar sharks, are yet to be recorded live due to visibility limitations (underwater visibility in 2009 was 5m., whereas in 2010 it has dropped to below 1 meter in places hindering all observation efforts) However conversations with local fishermen point to the fact that these elusive animals are inhabiting the Gulf, yet keeping mainly to the spots where the cages are. Talking to Prof. Ali Cemal Gücü of METU, we have discovered that these animals have historically used the area around the antique city of Iasos and the cove of Kıyıkışlacık, as their nursery, mostly due to its soft sedimentary basin, and naturally protected inner placement. The locals from Kıyıkışlacık back this proposal, by sharing with us personal accounts of their "swim with the sharks" from their childhoods.
In addition to all this information, should a meticulous scientific study be undertaken on the biodiversity of the region, we are certain, several other sensitive and endangered species will be discovered. This hypothesis is also backed by Doç. Dr. Murat Bilecenoğlu of Adnan Menderes University, who, following skin dives in the region has declared that the region is biologically more diverse than Fethiye Gulf, which is currently under protection.
A dead specimen of Rhinobatos cemiculus, found on September 2010 washed to shore with its head severed and the body cast aside, unfortunately proves true our concerns of the threats the sensitive species in the region face, and by which means their population is being depleted.
