After my blog post on “Gérard Le Bouëdec’s sociétés littorales” appeared in April, Olivier Le Gouic wrote me to point out that much more had been published in this area. An entire edited volume, Entre terre et mer, appeared in 2004.  I will continue, albeit gradually, to explore and review the French scholarship in this blog.
We shouldn’t be surprised that ordinary people in the early modern era were pluriactive; it was one of the best strategies to scavenge enough calories to stay alive, or to earn enough money to buy a regular supply of food from others. If the beach was a familiar place for Breton farmers, this was because they needed to collect seaweed to fertilize their fields, or even as kindling to heat their homes.  In this and in other aspects of the subsistence economy, coastal harvesting was an extension (prolongement naturel) of farming. 
But one thing that stands out about Entre terre et mer is the way in which some of the contributors explicitly interweave pluriactivity and environmental history. Marie-Anne Vandroy-Fraigneau remarks that the complimentary activities on land and sea followed a precise calendar, and indeed that each species of fish imposed its own rhythm through its unique tempo of spawning or migration.  Thus, another way to read pluriactivity is as an expression of seasonal fluctuations in the availability of food harvests from different sources and ecosystems. Fisher-farmers (or farmer-fishers) are surfing those waves of calories as they peak and recede.
I was reminded of this approach when I read Cathryn Pearce’s book on Cornish Wrecking. Pearce found that a great deal of the printed material about wrecking sought to “raise issues about the immorality of the coastal poor.”  This is putting it mildly. These communities have, too often, been depicted as if they did nothing but pillage shipwrecks, killing anyone who stood in their way. The language employed was shrill enough that she compares it to fears of cannibal tribes and she even nods to the Birmingham School concept of a “moral panic.”
Pearce seeks to normalize wrecking and situate it in its original context. She develops several key points. First—in Cornwall, at least—helping yourself to goods and saving lives were not considered incompatible activities. A “popular morality included lifesaving and charity to the shipwrecked,” extending at times to receiving them as guests in one’s own home and even parting with one’s own blanket if necessary. However, “payment in kind was extracted” in the form of so-called plunder from the wreck.  Second, informal custom was reinforced by actual legal rights enjoyed by manorial lords to harvest items found on shore or floating within sight of shore. Wreckers often believed themselves to be well within the bounds of the law. Third, bountiful wrecks were not such routine events that a whole community could have made a living off of plundering them.  An unusually stormy season might bring in a lot of wrecks, whereas a run of calm weather would leave the beaches empty.
Once again, we see that the rhythms of nature offered feast at some times, but famine at others. There is an interesting opportunity here to cross-reference wrecking (and wreck litigation) with what is recorded about weather patterns; did larger fluctuations like El Niño, or big freezes like the winter of 1786, result in spikes in the number of wrecks? Not only did coastal communities have to learn to step in time to the rhythms of nature, they had to take into account interruptions and aberrations in those rhythms as well.
John Gillis has remarked on the versatility of coastal peoples, which he takes as a sign of their exceptional intelligence. Perhaps the prevalence of jack-of-all-trades behavior says more about the exigencies of the seasons; on the coast, one learns to keep an eye out, and seize opportunities as they present themselves.
 Christophe Cérino, Aliette Geistdoerfer, Gérard Le Bouëdec and François Ploux, eds., Entre terre et mer: Sociétés littorales et pluriactivités (XVe-XXe siècle) (Rennes: Presses Universitaires de Rennes, 2004).
 Marie-Anne Vandroy-Fraigneau, “Quand la pluriactivité brouille les efforts de définition: gens de mer ou gens de côtes?” in Cérino et al., eds. Entre terre et mer, 190.
 Olivier Levasseur, “La pluriactivité sur le littoral septentrional de la Bretagne d’après les rapports de Le Masson du Parc (1726): premiers résultats,” in Cérino et al., eds. Entre terre et mer, 125-6.
 Vandroy-Fraigneau, “Quand la pluriactivité brouille,”191-192.
 Cathryn J. Pearce, Cornish Wrecking, 1700-1860: Reality and Popular Myth (Woodbridge: Boydell, 2010), 193.
 Pearce, Wrecking, 111.
 Pearce, Wrecking, 154.