There is now proof that birds do carry killifish eggs and distribute them to other waters.

     An article in Hakai Magazine, a coastal science and societies magazine, in 2019 details an fascinating study where swans ingested killifish eggs in a mix of corn and later the eggs were found still fully viable in the droppings of the birds. 

     According to the article “German naturalist Carl Christian Gmelin posited that ducks spread fish to distant waters by carrying fish eggs stuck to their beaks.”  and “British naturalist Alfred Russel Wallace wrote that freshwater fish eggs being carried by birds could be one of several means by which the same fish species wind up in distinct rivers.”

     Apparently two types of killifish eggs were tested in a study by Giliandro G. Silva, a doctoral student at the University of the Sinos Valley in Brazil.   Of five eggs found in the droppings of the swan, one hatched into a viable fry, essentially proving this is a way killifish distribution can be spread.

               Geo-historically, this study could lead to speciation over thousands of years.

LINK TO ARTICLE   

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     Frans Vermeulen worked in conjunction with Jean Huber and Meija to redescribe Rivulus pacificus.  Two new species, Rivulus gomesi n. sp., and Rivulus paradiseus n. sp., were also described in this paper.

   
According to: 

Rivulus pacificus
Photo by Frans Vermeulen

Killi-Data Series 2023, 74-100, 14 figs.

Following new collections in coastal and inland north-western Colombia, Rivulus pacificus Huber, 1992, is redescribed based on live nearby topotypes, then redefined in a restricted sense, and two new cryptic congeners, also from the Colombia lowlands, are described as Rivulus gomesi n. sp., and Rivulus paradiseus n. sp., both from the north-western lowlands, in the Atrato river system, near Chigorodó, Antioquia for the former and in the Acandí river basin, facing the Caribbean coast near Acandí, close to the Panama border, for the latter. The three species form a group of closely related species, not morphologically related and not pattern-wise related to the elegans species group, dominant in the Northern Colombian Andes and inter-Andean valleys and vicariant. Instead, they are morphologically more related to the micropus species group with a huge distribution in northern and north-eastern South America. The three species are not separable by morpho-meristics but are diagnosed by a combination of pattern characters in male and female. R. gomesi is mainly separated from the similarly-morphed pacificus by the presence of a supracaudal ocellus in females and by body pattern (red lines faint and irregular vs. fully lineated in pacificus males) ; R. paradiseus mainly differs from R. gomesi, also with a supracaudal ocellus in female (unlike pacificus, missing one), by body pattern (5 to 6 evenly interrupted red lines vs. irregularly scattered red lines and by posterior Anal fin and basal Caudal fin with reticulated inner (green spots, not red) pattern vs. few red dots. R. gomesi and R. paradiseus do fit well into the micropus group according to latest evidence. On the contrary, the elegans species group differs in Colombia from all members of the micropus group by having a more forward set Dorsal fin relative to the Anal fin; truncated Caudal fin vs. rounded; a larger maximum size (up to 90 mm TL vs. 63 mm TL on average. The 3 species of the R. pacificus group are separated notably from vicariant R. elegans and its 3 allied (chucunaque, sucubti, that taxon being formally proposed as a junior synonym of chucunaque, and leucurus) by live pattern and morphology. Hypotheses to explain the present distribution are forwarded.

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     A recent 2023 article “Enhancing mosquito predation activity of Mediterranean banded killifish (Aphanius fasciatus) by tidal recirculation runnels in the Po River Delta area” by Rodolfo VERONESI, Nicola PANDOLFI, Alberto ALBERANI, Romeo BELLINI Medical and Veterinary Entomology Department, Centro Agricoltura Ambiente “G. Nicoli”, Crevalcore (BO), Italy” discusses using Aphanius fasciatus for mosquito control in Italy.

Aphanius fasciatus picture found on Bing.com.

ABSTRACT:  Nature-protected coastal plain areas in the Po River Delta, Italy, are subjected to periodic flooding. Such phenomena create temporary water habitats conducive to the development of salt marsh mosquitoes, such as Aedes caspius (Pallas) and Aedes detritus (Haliday), which cause significant nuisance impacting the tourist industry.  Mosquito control is therefore required, but conflict arises about the need to safeguard endangered bird species typically nesting in the wetlands. Despite the fact that adopted mosquito control methods are designed to cause as little disturbance as possible, authorities responsible for nature conservation require that the possible impact of larval control activities are further reduced. These concerns have served as an incentive to seek out alternative control strategies, such as the enhancement of the predatory action of fish species inhabiting the salt marsh biotopes. The most abundant of these species is the native Aphanius fasciatus (Valenciennes) (Cyprinodontiformes Cyprinodontidae). The access of fish to isolated pools and lowlands subjected to occasional flooding can be promoted by connecting them to major permanent water bodies via shallow ditches or runnels, which are dug by hand. The results of four years of observations and larval sampling in a salt marsh area of about 4 ha, located in the natural reserve of “Sacca del Bellocchio” where a system of runnels has been planned and constructed, suggest that runnelling can be an effective, long-lasting larval control method, favouring the predatory action of fish.

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