How do the life cycles of salmon, trout, pikes, and mudminnows differ?

The life cycles of these protacanthopterygian fishes differ primarily in their environmental requirements and migratory behavior.

Freshwater Restriction vs. Migration

• Pikes and Mudminnows: Unlike many other protacanthopterygians, the pike family (Esocidae) and the mudminnow family (Umbridae) are completely restricted to fresh water throughout their entire life cycles. Pikes typically spawn in weedy shallows during late winter and spring.12
• Salmons and Trouts: These fishes demonstrate a transition between freshwater and marine environments. While all salmonids spawn in fresh water, many species are anadromous, migrating to the ocean to grow and mature before returning to their home streams to spawn. However, some populations—such as certain rainbow trout or lake trout—complete their entire life cycle in fresh water.13

Reproductive Strategies

• Salmonids: Due to the harsh, cold, and swift rivers they often utilize for spawning, salmon and trout have evolved to produce fewer, larger eggs (4 to 8 mm) and exhibit nest-building behavior to protect their embryos.1
• Environmental Adaptation: Reproductive behaviors and egg characteristics are shaped by natural selection. Species in more benign environments, such as lakes, generally produce more numerous, smaller eggs.1