Ecological Risk of Heavy Metals in Sediment Around Techeng Island Special Marine Reserves in Zhanjiang Bay

The concentrations of five metals(Cu, Pb, Zn, Cd and Hg) were measured in sediments obtained before and after the establishment of Techeng Island Special Marine Reserves(TCISMR) in Zhanjiang Bay to evaluate the ecological risk of heavy metals. The results showed that average values of potential ecological risk indexes of heavy metals at all stations increased slightly from 32.09 to 30.54 after establishment of TCISMR. Optimal semivariance simulation showed that the contents of five heavy metals have strong spatial correlations in August 2010(before), while this correlations weakened in April 2013(after establishment of TCISMR), suggesting that the main sources of heavy metals changed. The Hakanson Risk Index(HRI) values in Donghai levee, central and southern parts of Zhanjiang harbor were high up to 60.13 and 46.46, respectively. And Zhanjiang Bay Channel, the areas around special marine reserves, the artificial reef areas and mangrove areas at south of Techeng Island are the areas with low ecological risk and high ecological value, which should be treated as the prior ecological protection areas. Our study provided a priority control pattern of heavy metal pollution in TCISMR, which greatly benefits the sustainable development and resource protection in Zhanjiang Bay.

Optimal effort,fish farming,and marine reserve in fisheries management

In this paper,we develop a bioeconomic model to determine an optimal wild catch harvest and freshwater commercial aquaculture production in a lake that uses cages or floating rafts.Although off-bottom aquaculture activities have less impact on the environment compared to on-bottom aquaculture,it has negative externalities.It takes away the fishing area and hence creates pressure in the open-access fishing ground.It also changes the nutrient and ecological composition of the environment.We recommend the implementation of a reserved area to minimize the impact of fishing and aquaculture activities.The reserve also helps in improving the habitat and restocking the fish population which is declining rapidly.We determine the optimal sizes of the aquaculture and reserve and the optimal effort level that maximizes social welfare.We illustrate our findings using numerical simulations and perform an analysis of the optimal solutions with respect to biological and economic parameters involved in the model.

Estimation of age and growth and mortality parameters of the sea cucumber Isostichopus fuscus (Ludwig, 1875) and implications for the management of its fishery in the Galapagos Marine Reserve

The fishery of the sea cucumber Isostichopus fuscus was the most important one in the early 2000s in the Galapagos Marine Reserve.Its overexploitation leads to its total closure from 2016 to 2021.At the end of this period,if the co-management system of the Galapagos Marine Reserve decides to open this fishery,a total allowed catch must be established using the methodology of Wolff,Schuhbauer,and Castrejón(2012).The objective of this paper is to evaluate this methodology and improve the total allowed catch calculation.We replicated Wolff et al.‘s methodology that uses the Cadima equation of Maximum Sustainable Yield(in Troadec,1977).We determined the age and growth parameters of I.fuscus to estimate total mortality and improved the calculation of the area of fishing and habitat of this species in Galapagos to estimate its abundance.We found inconsistences in Wolff et al.‘s estimations of mortality and abundance and we recommend that the Maximum Sustainable Yield be used not as the total allowed catch,but as a limit reference point for this fishery.We propose,instead,to use a dynamic abundance model that is capable of estimating a variety of reference points,including the fishing mortality for optimal fishing that is recommended to use to establish a total allowed catch.In addition,for the first time,the age and growth parameters of I.fuscus for Galapagos and the eastern-central region of the Pacific Ocean are determined(L∞=42.5 cm;K=0.21/year).

Supervisory Monitoring of Ecological Environment of Marine Nature Reserve

According to the latest situation of marine nature reserves in China, major problems in the construction of China's marine nature reserves and causes were analyzed. Considering related laws and regulations as well as requirements of China's ecological environment protection, this paper pointed out the necessity and urgency of implementing supervisory monitoring over marine nature reserves, and suggested that Ministry of Environmental Protection should take the lead, marine, forestry, land resources and other departments in charge should cooperate to fulfi ll this task, the supervisory monitoring should cover ecological environment, protected objects, routine work of the nature reserve management agency, and the authority of supervisory monitoring results should be highlighted.

Eretmochelys imbricata:Lessons to Learn from a Monitoring Program in the North of Mozambique

Monitoring programs for nesting turtles around the world have been important to build up a matrix of information for better comprehension of their behaviour and dispersion. The Western Indian Ocean has several monitoring programs that are being used to reveal migration routes, phylogenetic interconnections and nesting behaviour patterns. We determined the nesting parameters for 69 records of hawksbill turtles collected during the Vamizi Island monitoring program. We also determined carapace measurements parameters of the turtles caught by fishermen in the area and give some considerations to improve the conservation of this species. Results show that the island receives hawksbill females all year long. Vamizi is a small nesting ground for this species, with an incubation period of 60.9 ± 10.6 days and a high reproductive rate. The turtles’ carapace measurements (SCL 42.0 ± SD 9.0 cm) revealed the existence of young individuals, foraging near the island, and their vulnerability to the fishing practices. This study strongly defends the need to identify more developmental and nesting spots, to be protected near Vamizi, to establish a solid network of marine reserves and corridors in the north of the Mozambique Channel.