A global review of marine recreational spearfishing

24 pages, 5 figures, 2 tables, supplementary information https://doi.org/10.1007/s11160-023-09790-7.-- Data availability: The full list of papers used for the systematic review is available as a supplementary tableRecreational spearfishing is a fishing method that occurs globally, yet receives considerably less attention in the scientific literature relative to other recreational fishing methods, such as angling. Lack of scientific information on spearfishing may negatively affect the development and management of marine recreational fisheries. We conducted a systematic review of 102 peer-reviewed papers published between 1967 and 2022 pertaining to marine recreational spearfishing. Based on this literature review, we provide an overview of key insights across social, economic, and ecological dimensions of marine recreational spearfishing. While spearfishers represent less than 5% of marine recreational fishers, the participants are younger and may differ from recreational anglers in their motivations, with suggestions of increased well-being generated from a close connection with the sea during underwater fishing. Recreational spearfishers mostly target species of moderate to high levels of vulnerability that are mid to high trophic level carnivores. Though spearfishers can deliberately target larger individuals of exploited populations, this is not a generalizable pattern. Despite a growing body of research on the ecological impacts of marine recreational spearfishing, there is limited knowledge of these effects and their mechanisms across biological levels of organization (e.g., individual, population, community and ecosystem) compared with those of other fishing methods. Recreational spearfishers can contribute to advances in marine ecological knowledge, and inclusive participatory management could represent a key step towards transformative sustainable development of marine recreational spearfishing. Throughout the review, we identify gaps in the research and areas where future research is needed to better inform the socio-economic importance, ecosystem impacts and future management of marine recreational spearfishingVS was supported by a “Juan de la Cierva Incorporación” (IJC2018-035389-I), and he is now supported by a “Ramón y Cajal” research fellowships (RYC2021-033065-I) granted by the Spanish Ministry of Science and Innovation. SV and PP are supported by the Xunta de Galicia (RECREGES I and II projects under Grants ED481B2014/034-0 and ED481B2018/017), Grupo de Referencia Competitiva GI-2060 AEMI, under Grant ED431C2019/11), and Fundación Biodiversidad, Ministerio para la Transición Ecológica y el Reto Demográfico, Gobierno de España (SICORE and GT PMR projects). VJG received a postdoctoral grant (#2017/22273-0) from São Paulo Research Foundation (FAPESP). MR would like to acknowledge Portuguese national funds from FCT—Foundation for Science and Technology through projects UIDB/04326/2020, UIDP/04326/2020 and LA/P/0101/2020. MR would also like to acknowledge FCT funding through a postdoctoral grant (SFRH/BPD/116307/2016). JACCN thanks to Meros do Brasil Project sponsored by Petrobras. FJH is supported by a Sȇr Cymru European Regional Development Fund Fellowship (80761-SU-135). RA was supported by the German Federal Ministry of Education and Research (Grants 01LC1826E and 033W046A). ML is supported by the Agencia Nacional de Investigación e Innovación (ANII, POS_EXT_2020_1_165362). This work acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S). [...] Open Access funding provided thanks to the CRUE-CSIC agreement with Springer NaturePeer reviewe

A novel method to obtain accurate length estimates of carnivorous reef fishes from a single video camera

In the last years, technological advances enhanced the utilization of baited underwater video (BUV) to monitor the diversity, abundance, and size composition of fish assemblages. However, attempts to use static single-camera devices to estimate fish length were limited due to high errors, originated from the variable distance between the fishes and the reference scale included in the scene. In this work, we present a novel simple method to obtain accurate length estimates of carnivorous fishes by using a single downward-facing camera baited video station. The distinctive feature is the inclusion of a mirrored surface at the base of the stand that allows for correcting the apparent or "naive" length of the fish by the distance between the fish and the reference scale. We describe the calibration procedure and compare the performance (accuracy and precision) of this new technique with that of other single static camera methods. Overall, estimates were highly accurate (mean relative error = -0.6%) and precise (mean coefficient of variation = 3.3%), even in the range of those obtained with stereo-video methods

A novel method to obtain accurate length estimates of carnivorous reef fishes from a single video camera

In the last years, technological advances enhanced the utilization of baited underwater video (BUV) to monitor the diversity, abundance, and size composition of fish assemblages. However, attempts to use static single-camera devices to estimate fish length were limited due to high errors, originated from the variable distance between the fishes and the reference scale included in the scene. In this work, we present a novel simple method to obtain accurate length estimates of carnivorous fishes by using a single downward-facing camera baited video station. The distinctive feature is the inclusion of a mirrored surface at the base of the stand that allows for correcting the apparent or "naive" length of the fish by the distance between the fish and the reference scale. We describe the calibration procedure and compare the performance (accuracy and precision) of this new technique with that of other single static camera methods. Overall, estimates were highly accurate (mean relative error = -0.6%) and precise (mean coefficient of variation = 3.3%), even in the range of those obtained with stereo-video methods

Spatial coefficients of variation in counts.

<p>Coefficients of spatial variation in fish counts estimated by the mixed-effect models used to evaluate the effects of time-of-day and tidal level, and by the random-effect models used to estimate variability at different temporal scales.</p

Spatial and temporal components of variability.

<p>Standard deviations (SDs) of spatial and temporal components of variability, and their percent contribution (%VC) to total variance for each species. The number of replicates (i.e., number of reefs censused) for each species is indicated in the “Transects” column. The significance of the variance components is indicated in the column denoted with “p”: ns =  not significant (p>0.05), *  =  significant (p<0.05), **  =  highly significant (p<0.01), ***  =  very highly significant (p<0.001). The instantaneous variation was estimated as the residual error of the nested random models; therefore its significance was not evaluated.</p

The reproductive biology of Pinguipes brasilianus Cuvier, 1829 (Osteichthyes: Pinguipedidae) in temperate rocky reefs of Argentina

ABSTRACT Pinguipes brasilianus is a conspicuous and abundant rocky-reef fish inhabiting the Northern Patagonian gulfs of Argentina, Southwest Atlantic. This study describes its reproductive biology in this region. We made macroscopic and histological descriptions of the testis and ovary development, analyzed the evolution of the gonadosomatic index (GSI) in both sexes throughout the year, and estimated fecundity and length at 50% maturity for females. Pinguipes brasilianus is a multiple spawner with indeterminate annual fecundity and an extended reproductive season, encompassing austral spring and summer. Low GSI values in males (monthly means ranged between 0.11% and 0.75%) and low relative fecundity in female fish (between 2 and 44 oocytes/g) are consistent with a need of close proximity between male and female during oocyte fertilization, sexual courtship and with spawning in pairs and/or within reef crevices. The estimated length at 50% maturity (± SD) for females was 15.22 ± 0.43 cm total length. Although P. brasilianus shares the main reproductive features of its congeneric species Pinguipes chilensis , male GSI and female length at 50% maturity in P. brasilianus were markedly lower than those reported for P. chilensis , while relative and batch fecundity were greater in fish of the same size

Sampling design used to evaluate variability at different temporal scales.

<p>Scheme of the sampling design followed on each reef, for each of the five species censused in 12 reefs within Nuevo Gulf (A), and for <i>Pseudopercis semifasciata</i> censused in three reefs from San José Gulf (B).</p

Effects of Time-of-day and Tide on fish counts.

<p>Fixed-effect coefficients for levels afternoon and high-tide, and their significance (in parenthesis), and standard deviation (SD) of spatial and residual components of variability. The number of replicates (i.e., number of reefs censused) for each data set is indicated in the “Transects” column. Significance is indicated as: ns = not significant (p>0.05), *  =  significant (p<0.05), **  =  highly significant (p<0.01). Spatial variation was highly significant in all cases.</p

Temporal components of variability in counts.

<p>Coefficients of variation associated with different factors and temporal scales of variability in fish counts, estimated using mixed- and random-effect models fitted to census data for five reef-fish species. Soft grey bars represent the component of variation contributed by each temporal scale (with 95% confidence intervals) and darker grey bars represent the total (cumulative) variation of counts at each temporal scale. Note the different scale of the y-axis for <i>Nemadactylus bergi</i>.</p