Animals

The Iberian frog naturally lives in the Iberian Peninsula: that is what it means to be endemic to this territory. With a slender body and pointed snout, it can reach about 5.5 centimetres. Reproduction takes place in water, and the species prefers mountain streams with vegetation along the banks and rocky beds.

The photograph recorded in Rio Douro opens a window onto this discreet life. On its own, it does not demonstrate water quality: pollution and changes to riverside habitats are among the threats described by the University of Évora.

The description also highlights a dark stripe crossing the eye area, with a narrower pale stripe beneath. These are details to appreciate in a photograph without handling the animal.

In the palmate newt, Lissotriton helveticus, mating takes place in pond water. Parque Biológico de Gaia explains that in higher, colder areas, larvae may spend the winter in water before completing metamorphosis the following year. It feeds on small invertebrates. The municipal description of Cabreira mentions this species; the cycle described here is general biology, not reproduction observed in a local pond.

Two stages need to be distinguished. The Parque Biológico profile gives about fifteen days to a month between egg-laying and hatching; metamorphosis follows later. Hatching means leaving the egg, not completing larval development. The possibility of spending another winter in water shows why one calendar does not fit every set of conditions.

Fluviário de Mora describes the breeding migration of the Iberian barbel, Luciobarbus bocagei, to shallow, well-oxygenated water over sand, gravel or pebbles. It is a freshwater journey. The fish feeds on small bottom-dwelling animals, plant matter and detritus. Barbel were recorded in Cavez during the 2016–2017 survey; the behaviour described is general biology, not a migration observed at that point.

The journey does not contradict its preference for slower currents and moderate temperatures. The place used for living and feeding can differ from the one chosen for reproduction. The Fluviário profile places breeding between May and June as a general description of the species.

The barbel is omnivorous: besides bottom-dwelling invertebrates and plant matter, it may occasionally eat small fish. The same source notes that it can reach about one metre. This is a possible size for the species, not a measurement of the Cavez specimens.

Parque Biológico de Gaia describes Gobio lozanoi as a freshwater river fish that eats small invertebrates and usually measures about 12 centimetres. That is a typical size given in the profile, not the size of every individual or a measurement taken in Cabeceiras.

In the Cavez survey from 2016–2017, the gudgeon is among the six species recorded. Bringing that evidence together with its diet description invites a question about the river: which small animals sustain the fish? The profile does not identify the prey eaten at that point or demonstrate a relationship with every insect presented on this website.