Geology topics

Erik C. Franklin

Publications and source records attributed to Erik C. Franklin.

2 recordsLinked to original sources

USGS2017

What can volunteer angler tagging data tell us about the status of the Giant Trevally (ulua aukea) Caranx ignobilis fishery in Hawaii: revisiting data collected during Hawaii’s Ulua and Papio Tagging Project 2000-2016

Giant Trevally (ulua aukea) Caranx ignobilis is one of the most highly prized and frequently targeted nearshore species. However, there is very little information on its current status in Hawaiian waters. This study uses mark-recapture data collected as part of recreational angler tagging program conducted by the Hawaii Department of Land and Natural Resources-Division of Aquatic Resources during 2000-2012. Mark-recapture data were used to estimate von Bertalanffy growth curve parameters and survivorship. Growth curves generated from the markrecapture data suggested that Giant Trevally from the main Hawaiian Islands may be growing faster and reach a smaller maximum size than individuals in the Northwest Hawaiian Islands, but there are a number of issues rendering this conclusion uncertain. The survivorship of Giant Trevally was positively associated with age, in part due to ontogenetic habitat shifts that result in older fish moving to offshore habitats where they are less vulnerable to anglers. When compared to stock assessments performed using commercial landings data and fisheries-independent visual surveys, the mark-recapture data produced similar estimates for the average length of exploited fish, a metric highly negatively correlated to fishing mortality. These results emphasize the need for additional information on the biology of Giant Trevally in Hawaiian waters and suggest that the data collected from this recreational angler tagging program may be useful to generate reliable estimates of mortality for stock assessment purposes.

Hawaii↗

USGS2011

Growth anomalies on the coral genera Acropora and Porites are strongly associated with host density and human population size across the Indo-Pacific

Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

PLoS ONE↗