Browsing by Author "Godoy, Natalio"

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    Limited effects of management and ecological subsidies on the size-spectra of kelp forest fish communities
    (2024) Gartenstein, Simon; Perez-Matus, Alejandro; Heather, Freddie J.; Godoy, Natalio; Torres-Canete, Felipe; Catalan, Alexis M.; Valdivia, Nelson
    Animal body size influences key ecological processes across biological hierarchies. For instance, densities (N) and community biomass (B) are allometric functions of body mass (M). Energetic equivalence predicts that density scales with body size as N proportional to M-0.75 and that biomass scales with body size as B proportional to M0.25. However, the way fish size-spectra are influenced by external processes, such as ecological subsidies (e.g. nutrients from upwelling zones) and fisheries management, is not well understood. We investigated the relationship of body size with density and biomass of reef fishes associated with subtidal kelp forests of Lessonia trabeculata that were influenced by the separate and interactive effects of management (Territorial Use Rights for Fisheries [TURF] or open access) and upwelling regimes (upwelling or non-upwelling zones). Fish densities and lengths were recorded using underwater visual censuses. Within each of 4 locations, paired TURF and open-access sites were surveyed. We surveyed 18 fish species, encompassing 1511 individuals ranging between 2 and 6639 g. We observed that fish size-spectra deviated from energetic equivalence, as N proportional to M-0.32 and B proportional to M2.2, indicating that the contribution of large-sized fishes to community density and biomass was greater than that predicted by energetic equivalence. Multi-model inference suggested that TURF and upwelling scenarios had weak effects on fish size-spectra. Results indicated that fish communities may have access to external food sources beyond local kelp forests. In addition, size-spectra may be a spatially persistent attribute of these fish communities.
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    Territorial User Rights for Fisheries as Ancillary Instruments for Marine Coastal Conservation in Chile
    (WILEY-BLACKWELL, 2012) Gelcich, Stefan; Fernandez, Miriam; Godoy, Natalio; Canepa, Antonio; Prado, Luis; Carlos Castilla, Juan
    Territorial user rights for fisheries have been advocated as a way to achieve sustainable resource management. However, few researchers have empirically assessed their potential as ancillary marine conservation instruments by comparing them to no-take marine protected areas. In kelp (Lessonia trabeculata) forests of central Chile, we compared species richness, density, and biomass of macroinvertebrates and reef fishes among territorial-user-right areas with low-level and high-level enforcement, no-take marine protected areas, and open-access areas in 42 100-m subtidal transects. We also assessed structural complexity of the kelp forest and substratum composition. Multivariate randomized permutation tests indicated macroinvertebrate and reef fish communities associated with the different access regimes differed significantly. Substratum composition and structural complexity of kelp forest did not differ among access regimes. Univariate analyses showed species richness, biomass, and density of macroinvertebrates and reef fishes were greater in highly enforced territorial-user-right areas and no-take marine protected areas than in open-access areas. Densities of macroinvertebrates and reef fishes of economic importance were not significantly different between highly enforced territorial-user-right and no-take marine protected areas. Densities of economically important macroinvertebrates in areas with low-level enforcement were significantly lower than those in areas with high-level enforcement and no-take marine protected areas but were significantly higher than in areas with open access. Territorial-user-right areas could be important ancillary conservation instruments if they are well enforced.
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    The natural diet of Prolatilus jugularis inhabiting Lessonia trabeculata kelp forests of south-central Chile
    (2024) Gartenstein, Simon; Fica-Rojas, Eliseo; Perez-Matus, Alejandro; Godoy, Natalio; Torres-Canete, Felipe; Valdivia, Nelson
    Kelp forests support species-rich food webs that predator-prey interactions may sustain. Here, we analyze prey availability and stomach contents of the predatory fish Prolatilus jugularis in an unexplored subtidal kelp forest of Lessonia trabeculata in south-central Chile. In the kelp forest, 42 invertebrate taxa and 1016 individuals were observed. In the diet of P. jugularis, 21 taxa and 130 individuals were identified. Crustacea, particularly amphipods, were the dominant and more frequent taxa in the kelp forest and stomach contents. Annelida and Mollusca were also present in the kelp forest and diets but were less abundant. We did not find a statistically significant correlation between kelp forest and stomach-content prey abundances and frequencies. Also, dominance structure significantly differed between kelps and stomach contents. Our results indicate that P. jugularis could feed in other habitats outside the survey area. Seven predatory fish were sampled in the kelp forest. Pinguipes chilensis was the dominant fish, with 65% of the total fish biomass, followed by P. jugularis with 20%.
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    Using expert knowledge to propose recreational marine reef-fish management measures in Chile
    (2024) Estevez, Rodrigo A.; Godoy, Natalio; Araya, Miguel; Azocar, Cristian; de la Barra, Christian; Bardi, Francisca; Fernandez-Urzua, Francisco; Garcia, Marcelo; Hiriart-Bertrand, Luciano; Lomonico, Serena; Medina, Marianela; Naretto, Javier; Ojeda, F. Patricio; Pequeno, German; Ponce, Francisco; Pulgar, Jose; Perez-Matus, Alejandro; Rivera, Javier; Smith, Andres; Toro Da Ponte, Jorge; Torres-Canete, Felipe; Vasquez, Julio A.; Gelcich, Stefan
    Marine recreational fisheries often lack necessary information to perform assessments and develop sustainable management strategies. In Chile, although reef-fish fisheries have been signaled as overexploited, there are still no commercial or recreational regulations regarding bans, catch limits, or size limits. We implemented an expert elicitation protocol to propose management measures to regulate recreational reef-fish harvests of 17 reef-fish species. Sixteen experts estimated minimum legal sizes, temporal closures, and maximum number of individuals harvested per person per trip (known as "bag limits"). Experts also prioritized management measures for each of 17 reef-fish species. Maximum number of individuals harvested per person per trip varied between 1 and 7. In addition, permanent bans were recommended for some species, such as acha (Medialuna ancietae), pejeperro (Semicossyphus darwini), and San Pedro (Oplegnathus insignis). We concluded that information gathered through expert elicitation can play a key role to inform data-poor recreational fishery management. Expert elicitation protocols that include iterative process, based on individual estimates and an open expert discussion phase, provide the necessary enabling environment to identify a variety of management measures. While future challenges include the development of mechanisms to promote acceptability and compliance for recreational fisheries management, the approach presented here is important to initiate much needed discussions.