Comparación de la captura por unidad de esfuerzo (CPUE) para su manejo pesquero, del Mixínido “Bruja Pintada” (Eptatretus stouttii) en las temporadas de primavera y verano del 2010, 2011 y 2021 en la Costa Occidental de Baja California, México / Comparison of the catch per unit of effort (CPUE) for its fishing management, of the Mixinid “hagfish” (Eptatretus stoutii) in the spring and summer seasons of 2010, 2011 and 2021 in the Western Coast of Baja California, Mexico

Después del año 2011 destacando que por más de 9 años del cese a la actividad pesquera sobre el mixino Eptatretus stoutii, ha regresado el esfuerzo de pesca sobre este recurso en el año 2021. Con el fin de evaluar la abundancia relativa del mixínido, en el presente trabajo se comparan las capturas durante los meses de marzo, abril, mayo, junio y julio del 2010, 2011 y 2021 obtenidos en la pesca de fomento de la E. stoutii. Se analizaron las bases de dato históricas de las temporadas 2010 y 2011 en los meses mencionados; se procesaron hasta obtener la captura por unidad de esfuerzo en términos de captura por trampa, para después compararlo con los resultados de las capturas por unidad de esfuerzo del año 2021. Se determino que las mejores capturas se obtuvieron en el 2011 con 32,965 kg, empleando 31,680 trampas. En el 2021 se ha obtenido una captura de 9,150 kg con un esfuerzo de 19,604 trampas, dando como resultado un rendimiento superior en la CPUE a los años anteriores con 2.143 kg/trampa en comparación con 0.702 y 1.041 kg/trampa obtenido en el 2010 y 2011 respectivamente. Esto sugiere un posible aumento en número de organismos vulnerables a la pesca.

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish ( Eptatretus stoutii )

Hagfish eyes are markedly basic compared to the eyes of other vertebrates, lacking a pigmented epithelium, a lens and a retinal architecture built of three cell layers: the photoreceptors, interneurons and ganglion cells. Concomitant with hagfish belonging to the earliest-branching vertebrate group (the jawless Agnathans), this lack of derived characters has prompted competing interpretations that hagfish eyes represent either a transitional form in the early evolution of vertebrate vision, or a regression from a previously elaborate organ. Here, we show the hagfish retina is not extensively degenerating during its ontogeny, but instead grows throughout life via a recognizable PAX6 + ciliary marginal zone. The retina has a distinct layer of photoreceptor cells that appear to homogeneously express a single opsin of the RH1 rod opsin class. The epithelium that encompasses these photoreceptors is striking because it lacks the melanin pigment that is universally associated with animal vision; notwithstanding, we suggest this epithelium is a homologue of gnathosome retinal pigment epithelium (RPE) based on its robust expression of RPE65 and its engulfment of photoreceptor outer segments. We infer that the hagfish retina is not entirely rudimentary in its wiring, despite lacking a morphologically distinct layer of interneurons: multiple populations of cells exist in the hagfish inner retina and subsets of these express markers of vertebrate retinal interneurons. Overall, these data clarify Agnathan retinal homologies, reveal characters that now appear to be ubiquitous across the eyes of vertebrates, and refine interpretations of early vertebrate visual system evolution.

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

SUMMARYHagfish eyes are markedly basic compared to the eyes of other vertebrates, lacking a pigmented epithelium, a lens, and a retinal architecture built of three cell layers – the photoreceptors, interneurons & ganglion cells. Concomitant with hagfish belonging to the earliest-branching vertebrate group (the jawless Agnathans), this lack of derived characters has prompted competing interpretations that hagfish eyes represent either a transitional form in the early evolution of vertebrate vision, or a regression from a previously elaborate organ. Here we show the hagfish retina is not extensively degenerating during its ontogeny, but instead grows throughout life via a recognizable Pax6+ ciliary marginal zone. The retina has a distinct layer of photoreceptor cells that appear to homogeneously express a single opsin of the rh1 rod opsin class. The epithelium that encompasses these photoreceptors is striking because it lacks the melanin pigment that is universally associated with animal vision; notwithstanding, we suggest this epithelium is a homolog of gnathosome Retinal Pigment Epithelium (RPE) based on its robust expression of RPE65 and its engulfment of photoreceptor outer segments. We infer that the hagfish retina is not entirely rudimentary in its wiring, despite lacking a morphologically distinct layer of interneurons: multiple populations of cells exist in the hagfish inner retina that differentially express markers of vertebrate retinal interneurons. Overall, these data clarify Agnathan retinal homologies, reveal characters that now appear to be ubiquitous across the eyes of vertebrates, and refine interpretations of early vertebrate visual system evolution.HIGHLIGHTSHagfish eyes are degenerate but not degenerating, i.e. rudimentary but growingRetinal interneurons discovered implying ancestral hagfish had derived retinas & visionDespite lacking pigment, a Retinal Pigmented Epithelium homolog functions in hagfishRevised synapomorphies illuminate the dimly lit origins of vertebrate eye evolutionGRAPHICAL ABSTRACT