This is the first systematic assessment conducted on fouling communities to determine the current status of six non-native marine invertebrates that were first recorded in Hong Kong three decades ago. They include the solitary ascidian, Ciona intestinalis; the slipper limpet, Crepidula onyx; the bryozoan, Bugula californica; the Caribbean bivalve, Mytilopsis sallei; the Mediterranean mussel, Mytilus galloprovincialis; and the boring isopod, Sphaeroma walkeri. Field surveys were conducted at 31 locations during wet (2011) and dry (2012) seasons and included fouling communities on piers and mariculture zones from estuarine to oceanic zones. The sampling was conducted by using photo-quadrats, destructive quadrats and field observations. To detect temporal changes in the abundance and recruitment of the sedentary non-native species, three piers were monitored with permanent photo-quadrats and recruitment panels for a one year period. We examined the relationship between seawater quality data available for Hong Kong and the abundances of fouling and non-native species. Only four of the six target non-native species were recorded in this survey. The isopod Sphaeroma walkeri was common and widely distributed in fouling communities in Hong Kong, while Ciona intestinalis, Crepidula onyx, and Mytilopsis sallei were uncommon and mainly restricted to areas with intensive human activities and poor seawater quality. These findings suggest that near shore human activities and poor water quality could increase the risk of establishment of non-native species in Hong Kong's marine fouling communities.

Mangroves provide habitat to a variety of fish species, potentially enhancing fish production in small-scale fisheries. Fish production ecosystem services have been correlated with mangrove area and perimeter in many tropical locations; however, nothing has been published linking small-scale fish catch and mangrove descriptors in the southern Caribbean Sea. We correlated the environmental variables with experimentally derived catch per unit of effort (CPUE) and richness of fishes in the Colombian southern Caribbean Sea, an area not directly connected with other productive coastal habitats. We measured mangrove descriptors (area, perimeter, and above-ground carbon), water quality (salinity and total dissolved solids), and water column productivity parameters (chlorophyll a, seston, and zooplankton bio-volume). Mangrove area and zooplankton bio-volume were the main factors influencing the species richness of fish. Mangrove area was positively correlated with catches for three of the most common fish species in the local artisanal fishery: Ariopsis canteri Acero P, Betancur-R, and Marceniuk, 2017; Mugil incilis Hancock, 1830; and Sciades proops (Valenciennes, 1840), which represent ca. 22% of the total regional annual catch. Our results suggest the causal links between mangrove habitat and fishery production through a mangrove trophic contribution. A. canteri appears to be a mangrove-dependent species and M. incilis a mangrove-associated species. Results support managing or preserving mangroves in the most extensive areas in the southern Caribbean to sustain small-scale fishery resources used mainly for community sustenance where alternative resources are limited.

Estuaries are highly productive habitats that support fisheries production. However, the importance of mangrove carbon to estuarine consumers can differ considerably among systems. In this study, we used stable isotopes (δ13C, δ15N) to investigate the importance of mangrove carbon as an energy source to estuarine consumers in the Atrato River Delta, Colombia, an area where fringing mangroves dominate the coastline and where other productive coastal habitats that may otherwise support the food web are absent. Basal resources and consumers were collected from mangrove and nearshore habitats during the rainy season. Results revealed a food web with a maximum length of 4.6 trophic positions. Bayesian mixing models indicated that most consumers used a mixture of basal sources, which suggests intertwined energetic pathways. However, mixing models also indicated that some species relied more heavily on some basal sources than others and revealed trophic pathways (food chains). Mangrove carbon directly supported herbivorous crabs (Sesarmidae) and indirectly supported planktivorous fish (Engraulidae) and piscivorous fish. Mangrove carbon also contributed significantly to the diet of 2 of the most common fish species in the local artisanal fishery: Centropomus undecimalis (mean: 46%; credibility interval [CI]: 1-80%) and C. pectinatus (mean: 33%; CI: 1-78%). Our findings highlight that mangrove carbon can be an important food source in areas without other productive coastal habitats and can play an important role in sustaining the production of fisheries.

To gain a better understanding on the trophic ecology of New Granada sea catfish, Ariopsis canteri, and their linkage to mangroves, nitrogen and stable carbon isotopes (δ 15 N and δ 13 C), as well as Bayesian mixing models, were used to explore trophic dynamics and potential ontogenic feeding shifts across different size classes: class I (8-20 cm), class II (21-32 cm) and class III (>32 cm). The study area was the estuary of the Atrato River Delta, where information about fish ecology is scarce. The δ 13 C of size class I was lower (mean ± S.D. = −24.96 ± 0.69‰) than that of size classes II (−22.20 ± 0.90‰) and III (−22.00 ± 1.96‰). The δ 15 N of size class I was lower (mean ± S.D. = 8.50 ± 0.67‰) than that of size classes II (9.77 ± 0.60‰) and III (10.00 ± 0.66‰). Body size was positively and significantly correlated to δ 15 N and δ 13 C. Individuals with L T > 32 cm presented the highest estimated trophic position (3.8). Five-source mixing models indicated that for class I, the mean estimated contribution of macroalgae was the highest (6%-57% C.I.), and for classes II and III, the mean estimated contribution of macrophytes was the highest (3%-53% C.I. and 4%-53% C.I., respectively). Ontogenetic feeding shifts of A. canteri were confirmed evidencing decreasing intraspecific competition between small and large individuals. Results suggest that mangroves are a nursery and feeding ground habitat for this species and that mangroves support A. canteri mainly due to the substrate/habitat that supports sources in the food webs. These results can be used in ecosystem-based fishery management focused on the protection of extensive mangrove areas in the southern Caribbean Sea.

No abstract