Non‐Linear Thresholds Characterize the Relationship Between Reef Fishes and Mangrove Habitat

A significant obstacle to evaluating the importance of mangrove habitat to coral reef fishes has been the difficulty of disentangling its effects from other subtidal/nearshore habitats or human population pressures. Florida\u27s seascape, unlike most others, has been extensively surveyed and mapped, and there are reliable estimates of human population density. Despite many studies that have correlated reef fish abundance with nearby mangrove habitat, some researchers continue to question the importance of mangroves to reef fishes. Previous studies that have investigated the mangrove–reef fish subsidy effect have applied methods that either compared averages or examined linear relationships; yet there is a body of literature that indicates that the effects of habitat are characterized by thresholds and limiting functions. Here, we employed a generalized additive model to investigate whether species richness of 106 mangrove‐associated reef fishes is related to thresholds in the extent of nearby mangrove forests along the Florida Keys Reef Tract. In addition, we used linear discriminant analyses (LDAs) to examine the relationships between the occurrence of 77 reef fish species and extent of Florida mangrove forests. We found that after accounting for confounding factors, at scales \u3c20 km2, species richness declines with decreasing mangrove extent, whereas richness increases with increasing mangrove extent at scales \u3e80 km2. Results of our LDA suggested that at least 49 reef fish species (64% of focal species) were associated with higher nearby mangrove forest extent. Our results indicate that of all habitat attributes considered, mangroves played the most substantial role in the diversity of nearby reef fish populations. These apparent thresholds (i.e., non‐linearities) in the extent of mangrove forests should be incorporated into fisheries critical habitat management and emphasize the need to consider non‐linear relationships between fishes and their habitat

Florida Recreational Angler Perspectives on Resuming Harvest of the Protected Goliath Grouper, Epinephelus itajara

Despite uncertainties surrounding the protected Atlantic goliath grouper’s stock size and resilience, fishery managers are under pressure to end the harvest moratorium in place since 1990. The present study sought to measure the proportion of anglers interested in reopening the goliath grouper fishery and to identify key reasons for this interest. We also present an estimate of the amount that anglers would be willing to pay for a goliath grouper harvest tag. A survey was mailed to a random sample of Florida (USA) residents with a recreational fishing license. Approximately half of the respondents agreed that the goliath grouper should now be open to recreational take. A probit analysis indicated that the best predictor for the opinion the fishery should be open is the belief that there are “too many goliath grouper.” Also, more anglers agreed than disagreed that goliath grouper are eating “all the fish on the reef,” a belief that was related to anglers personally experiencing goliath grouper depredation. The mean willingness to pay for a goliath grouper harvest tag was estimated to be between $34 and$79. This information can be used to estimate the potential revenues available from a hypothetical tag system and can be compared with the economic value of goliath grouper in non-consumptive uses such as recreational diving

Reviewer interest in a manuscript may predict its future citation potential

Previous studies have investigated the relationship between editorial delay and eventual citations, and generally have found that longer editorial delays are related to fewer future citations. There are many reasons that editorial delay can occur, one such reason is the inability to find willing and able peer reviewers. While a previous study found that the most common reason for reviewers to decline is due to time constraints, it is unclear how reviewer interest and the potential to be cited are related. Here, we examined 4 years (2010-2013) of manuscripts submitted to the Bulletin of Marine Science and paired accepted articles with subsequent citation data. Our aim was to investigate: (1) the relationship between number of reviewer invitations and probability of acceptance, and (2) the limitation that number of reviewer invitations may have on citation rates (citations per year). Our findings suggest that the number of reviewer invitations sent is not related to the probability of manuscript acceptance. However, we found that the number of reviewer invitations sent may signal a limit on the number of citations per year. After seven reviewer invitations, there was a substantial drop in the potential of higher citation rates. We hypothesize that reviewer interest in a manuscript may serve as a predictor of the potential citations an article will receive, and could be one of many mechanisms behind the editorial delay-eventual citation relationship. Additional research is needed to see if these patterns hold true over longer time periods and for other journal titles and fields

Measures of scholarly journal quality are not universally applicable to determining value of advertised annual subscription price

Both end users and authors commonly evaluate scientific journals based on several popular journal metrics. Such metrics, in particular the "impact factor," carry crucial weight in terms of which journals authors choose for submitting scientific works as well as to what titles an institutional library subscribes. While previous research has focused on the value of journals in terms of "price per page," no study has investigated the relationship between common journal metrics and the price a journal advertises for an annual subscription. In the present study, we took a linear modeling approach using Akaike information criterion to determine which journal metric (impact factor, Eigenfactor score, article influence score, total cites, or proportion reviews) was the "best" predictor of the advertised annual subscription price for scientific journals. Examining three differing scientific fields (aquatic science, sociology, and immunology) and accounting for for-profit versus not-for-profit status, we found results to be field-dependent. Total cites was the best predicting metric for the annual advertised subscription price for aquatic science and immunology, while the Eigenfactor score was the best predictor for sociology. We hypothesize the relationship with price changes with differing magnitudes of citation flows in a field. Clear from our study was that no single measure of journal quality is universally applicable to determine subscription "value."

An R package for computation of mangrove forest structural parameters using plot and plotless methods

Mangrove structure is influenced not only by the magnitude and periodicity of favorable energy inputs (temperature, hydroperiod, tides, sunlight, and nutrients), but also by stressors (salinity, drought, storms, and frost), which may have a diminishing effect on forest structure. In worldwide characterization of mangrove forests, researchers use several structural parameters to inform, compare, classify, and evaluate mangrove communities for both research and management. However, the calculation of these structural parameters involves a multi-step series of protocols and formula applications that are error-prone and time consuming. Using standard mangrove structure methodologies found in the literature, the mangroveStructure package for R was developed to deliver a simple tool to quickly calculate mangrove forest structure based on either plot or plotless methods. Outputs of the package include density, diameter, basal area, height, as well as relative values of density, dominance, frequency, and importance value. Output also includes common structural indices (complexity index and mean stand diameter) and visual representations of relative values, diameter and height histograms, and canopy height distributions along the transect line. This package will be useful to scientists interested in mangrove field surveys and those seeking a better understanding of mangrove ecosystems structural variability. To familiarize users with its many features, the package includes example data sets collected in the mangroves of Darien, Panama, and south Florida, USA

Contributing factors to long-term citation count in marine and freshwater biology articles

Researchers have investigated factors thought to affect the total number of citations in various academic disciplines, and some general trends have emerged. However, there are still limited data for many fields, including aquatic sciences. Using papers published in 2003-2005 (n = 785), we investigated marine and freshwater biology articles to identify factors that may contribute to the probability of citation and for cumulative citation counts over 10 years. We found no relationships with probability of citation; however, we found evidence that for those that were cited at least once, cumulative citations were related to several factors. Articles cited by books received more citations than those never cited by books, which we hypothesized to be indicative of the impact an article may have in the field. We also found that articles first cited within 2 years of publication received more cumulative citations than those first cited after 2 years. We found no evidence that self-citation (as the first citation) had a significant effect on total citations. Our findings were compared with previous studies in other disciplines, and it was found that aquatic science citation patterns are comparable to fields in science and technology but less so to humanities and social sciences

Lifting the goliath grouper harvest ban: Angler perspectives and willingness to pay

Despite uncertainties surrounding the protected Atlantic goliath grouper's stock size and resilience, fishery managers are under pressure to end the harvest moratorium in place since 1990. The present study sought to measure the proportion of anglers interested in reopening the goliath grouper fishery and to identify key reasons for this interest. We also present an estimate of the amount that anglers would be willing to pay for a goliath grouper harvest tag (the right sold to an angler to harvest one goliath grouper). A survey was mailed to a random sample of Florida (USA) residents with a recreational fishing license. Approximately half of the respondents agreed that the goliath grouper should now be open to recreational take. A probit analysis indicated that the best predictor for the opinion the fishery should be open is the belief that there are “too many goliath grouper.” Also, more anglers agreed than disagreed that goliath grouper are eating “all the fish on the reef,” a belief that was related to anglers personally viewing goliath grouper depredation. The mean willingness to pay for a goliath grouper harvest tag was estimated to be between $34 and$79. This information can be used to estimate the potential revenues available from a hypothetical tag system and can be compared with the economic value of goliath grouper in non-consumptive uses such as recreational diving

Diurnal patterns in Gulf of Mexico epipelagic predator interactions with pelagic longline gear: implications for target species catch rates and bycatch mitigation.

Bycatch in pelagic longline fisheries is of substantial international concern, and the mitigation of bycatch in the Gulf of Mexico has been considered as an option to help restore lost biomass following the 2010 Deepwater Horizon oil spill. The most effective bycatch mitigation measures operate upon a differential response between target and bycatch species, ideally maintaining target catch while minimizing bycatch. We investigated whether bycatch vs target catch rates varied between day and night sets for the United States pelagic longline fishery in the Gulf of Mexico by comparing the influence of diel time period and moon illumination on catch rates of 18 commonly caught species/species groups. A generalized linear model approach was used to account for operational and environmental covariates, including: year, season, water temperature, hook type, bait, and maximum hook depth. Time of day or moon phase was found to significantly alter catch rates for 88% of the taxa examined. Six taxa-swordfish (Xiphias gladius Linnaeus, 1758); tiger shark (Galeocerdo cuvier Peron and Lesueur, 1822); silky shark (Carcharhinus falciformis Muller and Henle, 1839); oilfish (Ruvettus pretiosus Cocco, 1833); bigeye thresher shark (Alopias superciliosus Lowe, 1841); and escolar (Lepidocybium flavobrunneum Smith, 1843)-exhibited higher catch rates at night, while eight taxa-skipjack tuna (Katsuwonus pelamis Linnaeus, 1758); wahoo (Acanthocybium solandri Cuvier, 1832); white marlin [Kajikia albida (Poey, 1860]; dolphinfish (Coryphaena sp.); yellowfin tuna (Thunnus albacares Bonnaterre, 1788); rays (Pteroplatytrygon violacea Bonaparte, 1832, Mobulidae sp.); lancetfish (Alepisaurus sp.), and blue marlin (Makaira nigricans Lacepede, 1802)-had higher daytime catch rates. These results reveal that shifts in effort between daytime and nighttime fishing (which are highly correlated with shifts between yellowfin tuna and swordfish targeting strategies) could have substantial, species-specific effects on bycatch rates. Whether driven by fishery conditions, market influences, or management measures, such temporal shifts in the timing of pelagic longline sets may have important implications for species-specific conservation goals and warrant further consideration

Graphic depiction of relationships between fish abundance and mangrove forest extent (note that mangrove extent on <i>x</i>-axis is rank-normal transformed).

<p>Shown are species-specific, best-fit linear mixed models determined via Akaike Information Criterion. Top six species are shown based on adjusted <i>R</i>² values. (A) <i>Haemulon plumierii</i>, (B) <i>Haemulon sciurus</i>, (C) <i>Sphyraena barracuda</i>, (D) <i>Lutjanus apodus</i>, (E) <i>Lutjanus griseus</i>, and (F) <i>Haemulon parra</i>. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142022#pone.0142022.s002" target="_blank">S2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142022#pone.0142022.s003" target="_blank">S3</a> Tables for information on models tested.</p

Mean annual rates of change in the abundances on reefs of 12 mangrove-dependent Caribbean fish species.

<p>Shown are the coefficients emerging from simple linear regression of the focal species’ abundances versus year. Negative coefficients indicate decline, positive coefficients indicate increase over the period of record (1993–2012). Note that relationships between abundance and time were universally weak (<i>R</i>² values <0.02).</p